V
THE ORNITHISCHIAN DINOSAUR •*•*
HYPSILOPHODON FROM THE
WEALDEN OF THE ISLE OF WIGHT
P. M. GALTON
BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
GEOLOGY Vol. 25 No. i
LONDON: 1974
22 JUL19!
THE ORNITHISCHIAN DINOSAUR
HYPSILOPHODON FROM THE WEALDEN
OF THE ISLE OF WIGHT
BY
PETER MALCOLM GALTON
^
Department of Biology
University of Bridgeport, Bridgeport
Connecticut 06602 U.S.A.
Pp. 1-152 ; 2 Plates ; 64 Text-figures
BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
GEOLOGY Vol. 25 No. i
LONDON: 1974
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BULLETIN OF I
THE BRITISH MUSEUM
(NATURAL HISTORY)
GEOLOGY
VOL. 25
1974-1975
TRUSTEES OF
THE BRITISH MUSEUM (NATURAL HISTORY)
LONDON: 1975
DATES OF PUBLICATION OF THE PARTS
No. i . . . . .16 May 1974
No. 2 . . . . .23 May 1974
No. 3 . . . . . .26 July 1974
No. 4 ..... 3 January 1975
No. 5 . . . . .19 May 1975
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CONTENTS
GEOLOGY VOLUME 25
No. i. The Ornithischian dinosaur Hypsilophodon from the Wealden of the
Isle of Wight. P. M. GALTON i
No. 2. The taxonomy and morphology of Puppigerus camperi (Gray), an
Eocene sea-turtle from northern Europe. R. T. J. MOODY 153
No. 3. The shell structure of Spiriferide Brachiopoda. D. I. MACKINNON 187
No. 4. Cretaceous faunas from Zululand and Natal, South Africa.
Introduction, Stratigraphy. W. J. KENNEDY & H. C. KLINGER 263
No. 5. A revision of Sahni's types of the brachiopod subfamily Carnei-
thyridinae. U. ASGAARD 317
An index is provided for each part.
THE ORNITHISCHIAN DINOSAUR
HYPSILOPHODON FROM THE WEALDEN
OF THE ISLE OF WIGHT
By PETER MALCOLM GALTON
CONTENTS
Page
I. INTRODUCTION ......... 5
II. MATERIALS AND METHODS ....... 6
a) Preparation ........ 6
b) Material ......... 6
c) British Museum numbers of previously figured specimens 10
d) Measurements ........ 12
III. THE Hypsilophodon BED ....... 15
a) Stratigraphy ........ 15
b) Hypsilophodon localities . . . . . . 17
c) Fauna ......... 17
IV. OSTEOLOGY OF Hypsilophodon foxii . . . . . 18
a) The skull and lower jaw . . . . . 21
i) INDIVIDUAL BONES ...... 21
ii) TEETH AND TOOTH REPLACEMENT . . . 4!
Dental formula . . . . . . 41
Premaxillary teeth . . . . . 41
Maxillary and dentary teeth ... 42
Special foramina and replacement teeth . 44
Sequence of tooth replacement ... 45
iii) ACCESSORY ELEMENTS ..... 46
Hyoid apparatus ...... 46
Sclerotic ring ...... 46
Stapes ....... 47
b) The vertebral column and ribs ..... 48
i) PROATLAS, ATLAS AND AXIS .... 48
ii) CERVICAL VERTEBRAE 3 TO 9 . . . 5!
Hi) DORSAL VERTEBRAE. ..... 56
iv) SACRAL VERTEBRAE ...... 57
V) SACRAL RIBS ....... 60
Vi) THE HEXAPLEURAL TYPE OF SACRUM 60
Vli) OTHER VARIATIONS IN THE SACRUM 6l
Vtii) CAUDAL VERTEBRAE AND CHEVRONS ... 63
c) Ossified tendons ........ 71
d) The appendicular skeleton ...... 72
i) THE PECTORAL GIRDLE ..... 72
ii) THE FORELIMB ...... 75
iii) THE PELVIC GIRDLE ...... 83
iv) THE HINDLIMB ...... 95
e) Dermal armour ........ 102
V. Camptosaurus valdensis, A LARGE Hypsilophodon foxii . . 102
THE WEALDEN HYPS1 LOPHODON
Page
VI. ASPECTS OF CRANIAL ANATOMY . . . . . . 103
a) The foramina of the braincase . . . . . 103
b) The paroccipital process and the post- temporal fenestra . 105
c) The eye ......... 106
d) Jaw musculature . . . . . . . no
i) ADDUCTOR MANDIBULAE GROUP. . . . IIO
ii) CONSTRICTOR DORS ALIS GROUP . . . . 112
iii) CONSTRICTOR VENTRALIS GROUP . . . 114
iv) M. DEPRESSOR MANDIBULAE . . . . 114
e) Kinetism ......... 114
f) Streptostyly . . . . . . . . 116
g) The antorbital fenestra . . . . . . 117
h) Jaw action ........ 119
VII. ASPECTS OF POST-CRANIAL ANATOMY . . . . . 122
a) Individual variation . . . . . . . 122
b) The first sacral rib . . . . . . . 123
c) Articulation and posture . . . . . . 124
i) FORELIMB ....... 124
ii) HINDLIMB ....... 126
iii) QUADRUPEDAL OR BIPEDAL POSE AND THE POSTURE
OF THE VERTEBRAL COLUMN . . . . 127
VIII. WAS Hypsilophodon ARBOREAL? ...... 130
a) Historical survey . . . . . . . 130
b) Summary of the purported anatomical evidence that
Hypsilophodon was arboreal . . . . . 133
c) Discussion of this evidence . . . . . . 133
i) GRASPING CAPABILITIES OF THE PES . . . 133
ii) GRASPING CAPABILITIES OF THE MANUS . . 135
iii) WIDER RANGE OF BRACHIAL MOVEMENTS POSSIBLE 135
iv) LARGE FORE-ARM SPACE ..... 136
v) RIGID TAIL AS A BALANCING ORGAN . . . 136
vi) DERMAL ARMOUR ...... 136
vH) LIMITED RUNNING CAPABILITIES . . . 136
IX. GENERALIZED FEATURES OF Hypsilophodon .... 137
X. SUMMARY .......... 142
XI. ACKNOWLEDGEMENTS ........ 144
XII. REFERENCES ......... 144
XIII. NOTE 149
SYNOPSIS
The anatomy of the primitive ornithopod Hypsilophodon is described. The femur described
as Camptosaurus valdensis is referred to Hypsilophodon foxii. The skull was possibly meso-
kinetic, metakinetic and amphistylic. The large antorbital fenestra was enclosed to a varying
extent in lower ornithopods to form a fossa for the M. pterygoideus. The jaw musculature was
typically sauropsid, the coronoid process is large and the jaw articulation offset. The mouth
was probably small with a cheek pouch lateral to the tooth rows. The teeth had sharp and
serrated leading edges and oblique but parallel occlusal surfaces with a high shear component
between them. There is a large amount of individual variation and the sacral count varies.
The massive first sacral rib strengthened the slender pubic peduncle of the ilium and keyed the
pubis to it. Hypsilophodon was definitely bipedal but probably ran with the vertebral column
held horizontally. The structure of the phalanges of the pes is not unique and the hallux was
ISLE OF WIGHT, ENGLAND 5
not opposable. Hypsilophodon was the most cursorial of the known post-Triassic ornithopods
and it was not arboreal. Hypsilophodon was probably not directly ancestral to any Cretaceous
ornithischian but structurally it is quite similar to the hypothetical Triassic ancestor of most
ornithischians other than Fabrosaurus.
I. INTRODUCTION
A slab of sandstone containing the partial skeleton of a reptile was discovered in
1849 at the top of the Wealden Marls near Cowleaze Chine, on the south-west coast
of the Isle of Wight, England. Mantell (1849) figured and described three cervical
vertebrae from this specimen as those of a very young Iguanodon. Owen (1855)
illustrated the complete block and described it as belonging to a young Iguanodon
mantelli. Fox exhibited more material from this same Wealden bed at the British
Association meeting at Norwich in 1868. This included a skull and various post-
cranial remains, which he identified as a new species of Iguanodon (Fox 1869).
Huxley (1870, abstract 1869) described and figured this skull, making it the type of a
new genus and species, Hypsilophodon foxii. He showed that a centrum from a
dorsal vertebra on this specimen was identical to those described by Owen, and he
therefore suggested that Owen's skeleton too belonged to Hypsilophodon. Huxley
separated Hypsilophodon from Iguanodon by differences in the teeth, vertebrae and
femur and in the number of metatarsals. He showed the parallel position of the
pubis and ischium and the obtuse angle between these two bones and the anterior
part of the ilium, the first time that this typically ornithischian condition had been
shown.
In 1873 Hulke collected some additional material that formed the basis of two
papers (1873, 1874) ; the first dealt mainly with the teeth and appendicular skeleton
and the second with the skull. He noted that Hypsilophodon differed from Iguano-
don in having four metatarsals, in the shape of the unguals, in having longer phalanges
in the hind foot, a tibia longer than the femur and in the more proximal position of
the inner (fourth) trochanter of the femur. In the discussion following Hulke (1873),
Owen denied the generic separation of Hypsilophodon and referred to it as Iguanodon
foxii. He stated that generic identity was shown by the similarity in tooth shape and
wear, with the enamel layer on opposite sides in the upper and lower jaws, and by the
peculiar spout-like form of the edentulous anterior end of the mandible. Owen
(1874) elaborated these points when he described the skull of Hypsilophodon as that
of Iguanodon foxii. Hulke (1882), in his attempt at a complete osteology, figured
most of the important material and described the individual elements.
Lydekker (1888) catalogued the material of Hypsilophodon in the British Museum
(Natural History). Nopcsa (1905) discussed certain aspects of the anatomy while
von Huene (1907) figured the ilium and ischium. Abel in 1911 reconstructed the
forearm and hand, and the foot in 1912. He argued (1912, 1922, 1925, 1927) that
Hypsilophodon was arboreal, a conclusion that was followed and expanded by
Heilmann (1916) and Swinton (1934, 19360, b) although Heilmann later (1926)
disagreed.
Reconstructions and restorations of Hypsilophodon are given by Hulke (1882),
Smit (in Hutchinson 1894), Marsh (1895, 1896^, b), Heilmann (1916), Abel (1922 and
6 THE WEALDEN HYPSILOPHODON
later), von Huene (1956), Wilson (in Oakley & Muir-Wood 1959), Ostrom (1964)
and Colbert (1965). General accounts are given in Swinton (1934, 19360, b, 1954,
1962) and with one exception (i936&) these are accompanied by restorations. He
also (1936) described the maxilla, teeth, pectoral girdle and limbs from two fairly
complete skeletons in the Hooley Collection acquired by the British Museum
(Natural History). Mounts were made of these two skeletons, photographs of which
were published by Swinton (1934, 19360).
Because of its primitive structure and supposedly arboreal mode of life, Hypsilo-
phodon is an especially interesting dinosaur and, as indicated above, it has been the
subject of numerous papers. However, the available account of its anatomy is still
far from complete despite the fact that it is the best represented British dinosaur.
This paper is the result of further preparation and study of the specimens available ;
there are twenty individuals represented by articulated bones, including one almost
complete skeleton and two good skulls. The study of the pelvic musculature of
Hypsilophodon, with a consideration of the functional significance of the prepubic
process of ornithischians, has already been published (Galton 1969). The mode of
life of Hypsilophodon has also been discussed elsewhere (see p. 149).
II. MATERIAL AND METHODS
a) Preparation
Apart from the material noted on page 10 all the remains of Hypsilophodon are
in the British Museum (Natural History) and the appropriate specimen numbers are
used in this paper. With the exception of R5829 and R5830 all articulated remains
were in blocks with the bones exposed on the surface. The slab (28707) figured by
Owen (1855) has been left unprepared to show the original appearance of these
blocks. Hulke (1882) figured all the other important blocks ; these were developed
further so that now, in most cases, the bones are completely free of matrix. Mechan-
ical preparation was used on most of the material. The matrix of blocks with
articulated remains was a hard sandstone which prepared well in 10 per cent acetic
acid, following the methods developed by Toombs (1948) and Rixon (1949). Poly-
butyl methacrylate dissolved in methylethyl ketone was used to strengthen and har-
den the bone, with Glyptal as an adhesive. Acid preparation was used on Ri93,
Ri95, Ri96, Ri97, Rig8, R200 and R2477.
b) Material
There are many isolated bones of Hypsilophodon in the British Museum (Natural
History) collection but most are incomplete and badly preserved. Details of all the
material are listed by Galton (1967). Diagrams showing the amount of each bone
preserved in specimens 28707, Ri92, Ri93, Ri95, Rig6, R200, R2466-76, R2477,
S.M. 4127, R5§29 and R5830 are given as well as a table listing all the skull bones in
the collection (Galton 1967, figs. 5-18). The following list contains only specimens
referred to in the literature or in this paper and the author and plate or figure numbers
ISLE OF WIGHT, ENGLAND 7
are given. For details of the actual bones figured reference should be made to Sec-
tion (c) in which all previous figures are listed with the relevant specimen numbers
(not given in papers prior to 1936) and an indication of the bones concerned.
Mantell Collection, purchased 1853
28707, 39560-1. This specimen will be referred to as 28707 and is the paratype
(Huxley 1869). Slab of sandstone with an articulated skeleton consisting of a
partial vertebral column, pelvic region and hindlimbs. Found in cliff about 100 yd
west of Cowleaze Chine, Isle of Wight (Owen 1855 : 2). Figured by Mantell (1849,
pi. 29, fig. 9*), Owen (1855, pi. I - complete block; pi. 15, fig. 8), Huxley (1870,
pi. i, figs. 6-8 ; pi. 2) and Hulke (1882, pi. 74, figs. 1-4).
36509. Distal end of right femur, matrix a soft red sandstone, from Cuckfield,
Sussex. This specimen was referred to Hypsilophodon by Lydekker (1888) and was
the only specimen not from the Isle of Wight. However, this femur has a deep
anterior intercondylar groove, and is therefore not referable to Hypsilophodon (see
Text-fig. 54) ; this means that the genus has not been found outside the Isle of Wight.
Fox Collection, purchased 1882
R167. Large left femur, ends imperfect (PI. 2, fig. 4), referred by Lydekker (1888)
to Hypsilophodon but subsequently (1889) made the type of Camptosaurus valdensis.
The generic position of this specimen is discussed in Section V.
R170. Left tibia, listed by Lydekker (1888) as right but corrected later (1891).
The 1888 catalogue also lists under Iguanodon for this number ' Three specimens of
the distal extremity of the humerus of very young individuals'. Material actually
consists of a distal end of a left tibia, two proximal and two distal ends of femora,
distal end of a humerus and a distal end of the third metatarsal - all Hypsilophodon.
R183. An ulna of Hypsilophodon according to Lydekker (1888) ; but actually the
fourth right metatarsal of an ornithopod.
R184, R185. Associated pair of femora listed by Lydekker (1888). These are
ornithopod but not Hypsilophodon.
R186. Right tibia, listed by Lydekker (1888) as a left tibia which was apparently
associated with the femora Ri84 and Ri85. Corrected to right tibia when Lydekker
(1891) referred it to the coelurosaur Calamospondylus foxi ; Ri86 was obviously not
from the same animal as the femora !
R189. Part of right ramus of mandible found about 210 yd east of Barnes High
(Fox in letter quoted by Owen 1874 : 13). Figured by Owen (1874 : 2, figs. 8-u).
R190. Right mandibular ramus, two caudal vertebrae and parts of ribs on a sand-
stone slab. Found about 150 yd east of Barnes High (Fox, letter quoted by Owen
1874 : 13). Figured by Owen (1874, figs. 1-2).
R191. Tooth from Rigo figured by Owen (1874, pi. 2, figs. 12-17).
8 THE WEALDEN HYPSILOPHODON
R192. Block with articulated bones of pectoral girdle, forelimbs, neck and jaws with
various disarticulated skull bones of a large individual. Also other blocks with
parts of pelvis and hind limbs ; all the bones are poorly preserved. From Hypsilo-
phodon Bed (Fox MS) ; main block figured by Hulke (1882, pi. 73).
R192a. Large left femur that does not belong to same individual as Riga because
latter already includes two femora. From Hypsilophodon Bed (Fox MS) ; figured
by Hulke (1882, pi. 78, figs. 1-5).
R192b. Ilium and prepubic process from an extremely young individual.
R193. Block with articulated bones of pelvis, hindlimb and tail. From Hypsilo-
phodon Bed ; figured by Hulke (1882, pi. 77), Galton (1969, figs. 4, 6-n, 13, 15) and
Text-figs. 24, 250, 26B, C, 30, 31, 49, 50, 53A, B and 55.
R194. Block with skull elements, right humerus and radius. From Hypsilophodon
Bed (Fox MS) ; incorrectly listed by Lydekker (1888 : 194) as 'an imperfect pelvis
and bones of the hind limb'. Figured by Hulke (1882, pi. 72, fig. i) as an eroded
internal aspect of skull but actually the external aspect. Partial basis for Text-fig. 9.
R195. Block with pelvic region from Hypsilophodon Bed (Fox MS). Figured by
Hulke (1882, pi. 76) and Text-figs. 25 A, B, E, F, 26A, 27, 46, 47 and 52.
R196, R196a. Two blocks (for photographs taken before preparation see Galton
1967, figs. 19-21) which together contained a practically complete articulated skele-
ton (Ri96) plus the posterior half of a tail from a larger individual (Rig6a.) ; from
Hypsilophodon Bed (Fox MS). Rig6 figured by Hulke (1882, pi. 72, fig. 2 ; pi. 74,
fig. 13 ; pi. 75 and pi. 79, figs. 2-3), Nopcsa (1905, fig. i), Abel (1911, fig. 12 ; 1912,
fig. 12), Galton (1970, fig. 56 ; in press a, figs. 5A, B) and Text-figs. 12, 13, 19-23, 256,
26D, 28, 29, 33-35, 37, 3§, 40, 4*> 4$A, 51, 536, D, 58 and PI. 2, fig. 3 ; Rig6a by
Hulke (1882, pi. 74, fig. 13) and in text-fig. 62.
R197. The holotype, a skull of a small individual plus a partial atlas, a cervical
vertebra and a dorsal centrum. Found about 210 yd east of Barnes High (Fox in
letter quoted by Owen 1874 : 13). Figured by Huxley (1870, figs. 1-5), Owen
(1874, pi. i, figs. 9-10 ; pi. 2, figs, i, 5), Hulke (1882, pi. 71, figs. 2-4) and in Text-fig.
2.
R199. Left tibia of large individual, listed as right by Lydekker (1888) but later
corrected (1891). From Hypsilophodon Bed (Fox MS) ; figured by Hulke (1882,
pi. 80, fig. 2 ; pi. 81, fig. i).
R200. Left and right hind-feet of large animal (s) from Hypsilophodon Bed (Fox MS) .
These two feet are about the same size and the matrix is very similar but they may be
from different animals as they were given separate find numbers - I J (right) and IL
in Fox (MS) ; figured by Hulke (1882, pi. 81, figs. 2-3).
R202a. Imperfect dorsal vertebra listed by Lydekker (1888).
R752. Right tibia, listed by Lydekker (1888) as a left tibia but later (1891) cor-
rected.
R8422. Sacral centra i, 2 and 3 from a large individual, damaged, no data.
ISLE OF WIGHT, ENGLAND 9
Hulke Collection, purchased 1895
R2466-R2476. Parts of one small individual in soft grey marl. Found in cliff
about 100 yd west of Cowleaze Chine (Hulke MS : 40), not the west end of the Bed
as stated by Hulke (1874 : 18). All this material was described by Hulke (1873)
who figured some of it in that work (pi. 18, figs. 1-8) and again in 1882 (pi. 72, figs.
3-9 ; pi. 79, figs, i, 4) ; Nopcsa (1905, fig. 3) figured the only known predentary,
which is also shown in Text-fig, n.
R2477. Block which contained a skull with atlas and axis, dermal armour and two
vertebral series (a, b) each consisting of the posterior dorsals and the anterior sacrals.
Found on the beach between Barnes High and Cowleaze Chine after it had been rolling
about for some time (Hulke 1874). Figured by Hulke in 1874 (pi. 3, figs, i, 2) and
1882 (pi. 71, fig. i ; pi. 76, fig. 2) as well as by Nopcsa (1905, figs. 2, 4). Photo-
graphs showing the complete block before preparation plus the lateral and dorsal
views of the skull in the round are given by Galton (1967, figs. 22-25). The skull is
shown in Text-figs. 4-8, 12, 17, 60, 61, PI. i, and PI. 2, figs, i, 2 ; the atlas and axis
in Text-fig. 18 ; skull also in Galton (in press figs. 6-8).
R2481. Twelve centra and one complete cervical vertebra found near Cowleaze
Chine (Hulke MS). Figured by Hulke (1882, pi. 74, figs. 5-8).
Hooley Collection, purchased 1924
R5829. Nearly complete mounted skeleton (see Swinton 19360, fig. 2) of a large
individual ; bones slightly crushed. Found near Cowleaze Chine (Register B.M.
(N.H.) Collection and on card with Hooley Collection) and not from the Chine itself
as stated by Swinton (1936), who gives measurements and descriptions of some of
these bones.
R5830. Nearly complete mounted skeleton (see Swinton 1934, pi. 23 ; 19360,
fig. 2) of a small individual ; bones show practically no distortion, articular surfaces
are well preserved. Locality data as for R5829 ; bones figured by Swinton (1936,
figs. 4-7) and in Text-figs. 32, 36, 39, 42-45, 53E, 54, 56 and 57.
The manus as mounted contained phalanges of a pes but, because the hind-feet
are already complete, these extra pedal elements must belong to a second individual.
In the Hooley Collection there are several bones from a small individual (see Galton
1967, fig. 17) of which the state of preservation closely resembles that of R5830 ;
some of these correspond to elements which are missing from the mounted skeleton
and probably belong to it, others duplicate elements from the mounted skeleton
(see Galton 1967, fig. 16) and must belong to other individuals. All this material is
numbered R583O.
R5862. Left maxilla from near Cowleaze Chine (Register B.M. (N.H.) Collection),
figured by Swinton (1936, fig. i).
R5863. Part of left mandible from near Cowleaze Chine (Register B.M. (N.H.)
Collection) ; teeth figured by Swinton (1936, figs. 2, 3).
R6372. Intercentrum of atlas described by Swinton (1936) and five jaw fragments ;
from Cowleaze Chine (Register B.M. (N.H.) Collection).
10
THE WEALDEN HYPSILOPHODON
R8367. Isolated skull bones, no data ; isolated teeth, see Text-figs. 14-16.
R8419. Right exoccipital and paroccipital process, no data, see Text-fig. 9.
Other material
R8352. Distal part of large right femur with fourth trochanter, found near Cowleaze
Chine in the early 1960*5.
R8366. Many isolated bones from at least two individuals, one small and the other
medium-sized ; discovered about 100 m west of Cowleaze Chine in September, 1965
by a field party from the I3th Symposium on Vertebrate Palaeontology and Com-
parative Anatomy.
R8418. Skull elements and teeth from the above find, partial basis for Text-fig. 9.
Museum of the Geology of the Isle of Wight, Sandown, I.o.W. : Poole Collection,
donated 1938 - S.M. 4127. Part of tail and hind-limb from Cowleaze Chine, basis
for metatarsal V in Text-fig. 58 and for identification of distal tarsals in Text-fig. 57.
Department of Zoology, University College London : material found by a party
led by Dr P. L. Robinson.
Vertebrae and limb bones from at least three small animals all found in a few cubic
feet of the Hypsilophodon Bed. This material is badly preserved though much is in
natural articulation. Photographs show that the locality was about 100 metres west
of Cowleaze Chine in practically the same position as where R8366 was found.
c) British Museum (Natural History) numbers of previously figured specimens
three cervical vertebrae
complete block
dermal armour (as
integument)
skull and vertebra
caudal vertebra
pelvic region
front part of dentary
right scapula and coracoid
part of manus
teeth
right foot
skull and dermal armour
two vertebral series a and b
skull
skull
part of mandible
Mantell, 1849
pi. 29,
fig. 9*
28707
Owen, 1855
pi. i,
28707
Pl- 15,
fig. 8
28707
Huxley, 1870
pi. i,
figs. i-5
Ri97
figs. 6-8
28707
pi. 2
28707
Hulke, 1873
pl. 18,
fig. i
R2470
fig. 2
R24&7
fig- 3
R2473
fig. 4-7
R247I
fig. 8
R2466
Hulke, 1874
Pi- 3,
fig. i
R2477
fig. 2
R2477
Owen, 1874
pl. i,
figs. 9, ga, 10
Ri97
pl. 2,
figs, i, 5
Ri97
figs. 8-n
Ri8g
ISLE OF WIGHT, ENGLAND
Owen, 1874
Hulke, 1882
Nopcsa, 1905
von Huene, 1907
Swinton, 1934
Swinton, 1936
pi. 2, figs. 12-17
text-fig, i
fig. 2
pi. 71, fig. i
figs. 2-4
pi. 72, fig. i
fig. 2
figs. 3-5
Pi- 73
pi. 74, figs. 1-4
figs. 5-8
figs. 9-12
fig. 13
pl-75
pi. 76, fig. i
fig. 2
pi. 77
pi. 78, figs. 1-5
figs. 6-7
pi. 79, fig. i
figs. 2-3
fig. 4
pi. 80, fig. i
fig. 2
figs. 3-8
pi. 81, fig. i
figs. 2-3
fig. i
figs. 2, 4
fig- 3
pi. 23
fig. 330
fig- 33i
fig. i
figs. 2-3
Rigi tooth
mandibular ramus
caudal vertebra
R2477 skull, palate
Ri97 skull
Ri94 eroded skull
Rig6 part of left mandible
R247I teeth
Ri92 block with pectoral girdle,
neck, jaws
28707 three cervical vertebrae
R248i cervical vertebra
from Fox Collection but
originals could not be
found
Ri96a three caudal vertebrae
Ri96 pelvic region
Ri95 pelvic region
R2477 sacrum b
Ri93 right pelvic bones and foot
Ri92a left femur
from Hulke Collection but
originals could not be
found
R24&7 right scapula, coracoid,
humerus
Rig6 right fore-arm, left humerus
R2466 left foot
from Hulke Collection but
original could not be
found
Ri99 right tibia
originals could not be found
Ri99 right tibia
R2OO right and left foot
Rig6 braincase, occiput
R2477 occiput
R2470 right dentary with
predentary
? Rig6 reconstruction of ilium
Ri93 right ischium
^5830 photograph of mounted
skeleton
R5862 left maxilla
R5863 maxillary teeth
12
Swinton, 1936
Swinton, 19360
Gallon, 1969
Gallon, in press
THE WEALDEN HYPSILOPHODON
figs. 4-7
fig. 2
R583O scapula, coracoid, humerus,
radius, ulna, tibia, fibula,
astragalus, calcaneum
R5829 and photograph of the
R583Q
figs. 4, 6- n, 13, all Ri93
15
figs. 6-8
R2477
mounted skeletons
figures and stereo-
photographs of pelvic
girdle and femur to show
areas of muscle
attachment
skull
Outline figures of the skull (R2477) and limb bones (Ri96) are given in Galton
(19700, 19710, b, 1973, in press a ; see page 149).
d) Measurements
The proximal part of the femur gives the best indication of the relative size of
important specimens. In Table I the measurement given is the minimum distance
between the proximal end and the distal side of the base of the fourth trochanter
(Text-fig, if). In specimens where no femur was available this distance was cal-
culated by comparing other bones with specimens which have a femur ; the calculated
values are given in parentheses. The total length of R5830 was about -9 m, Rig6
about 1-36 m, R5829 about 1-8 m and Ri67 about 2-3 m. To facilitate comparison of
the sizes of different bones from the same specimen all the measurements are given
together in Tables II and III. Unless indicated to the contrary by a diagram in
Text-fig, i, L = greatest length, Mw = minimum width of shaft, Wd and Wp maxi-
mum width of distal and proximal ends. All measurements are in millimetres.
a
e
f
FIG. i. Diagram to show the basis for some of the measurements in Tables I and II :
a. scapula and coracoid ; b. humerus ; c. ilium ; d. ischium ; e. pubis ; f . femur.
ISLE OF WIGHT, ENGLAND 13
TABLE I
To show the relative size of the specimens of Hypsilophodon - measurements in mm of fourth
trochanter index of the femur, see Text-fig, if.
R583Q 43
Ri97 (49)
Rig6
Ri92a
65
76
R2466-76 (55)
R2OO
(81)
S.M. 4127 (57)
Ri92
± 82
R2477 skull (57)
Ri93
86
R2477a + 60
R5829
87
Ri95 62
Ri67
108
28707 64
TABLE II
Measurements of the bones of
the girdles
and the long
limb bones
(All
measurements in
mm)
Bone
Spec. No. L/R
L
Wp
Wd
Mw i
2
Scapula
R5830 L
70-5
-
-
10
(Text-fig.
la) R
(67-5)
24'5
25
- -
R24&7 R
88
32
26-5
12-5
Ri96 R
105
45
41
15
Ri92 R +
144
47
53
22
R5829 R
-
-
-
21
Coracoid
R5830 R
20-5
-
-
-
(Text-fig.
la) R24&7 R
26
30
-
-
Rig6 L
35'5
43
-
35
Ri92 R
43
-
-
- -
Humerus
R5830 L
(74)
17
15
26
(Text-fig.
ib) R
69
16-5
J4
6
Rig6 L
105
26-5
25
9-5 45'5
R
105
28
-
45-5
Ri92 L
147
+ 39
-
18 72
R5829 L
(159)
41
-
(64)
R
151
-
33
(68-5)
Radius
R5830 L
-
9'5
-
4
Ri96 L
82-5
I5(R)
13
6
Ri92 L +
in
-
-
8
R5829 R
114
-
-
- -
Ulna
R583o L
-
8
-
9-5
-
Rig6 L
88
11 '5
14-5
6 19
-
Ri92 L ±
125
-
-
ii 25
—
Ilium
Ri95 R
—
n-5
-
21 15
-
(Text-fig.
ic) Ri96 L
142
9
14
22 16
67
R2477^ R
-
-
-
23
-
Ri93 R
-
16
-
32 21
89(L)
THE WEALDEN HYPSILOPHODON
TABLE II (cont.)
Bone Spec. No.
L/R L Wp
Wd
Ischium R5830
L 102 25-5
8-5
(Text-fig, id) Ri95
L 36
-
Rig6
46
-
Ri93
R 49
-
R5829
R 197 53
21
Pubis Ri95
L 8
15
(Text-fig. le) Rig6
R 10
-
Ri93
R 38 14
-
R5829
L 36 12
-
Femur
(Text-fig, if) R583o
L 101 26-5
25
28707
L ± 150
-
Rig6
L + 150
-
Rig2a
L 173
-
R5829
R 202
56
L 198 52
-
Tibia Rs83o
R 117 26-5 (L)
25-5
Rig6
R
4°
SM4I27
R 170 33
36
Ri93
58(L)
R5829
L 238 (62)
45
R (242) (42)
_
TABLE III
Measurements of Manus and
Pes
(All measurements in mm)
R5830
R5830 R2466 SM4I27
Ri96
L
R L R
L
First f*L
_
metatarsal < Wp
_ _ _
_
[Wd 7
7 6 14
12
Phalanx I 18-5
_ _ _
28
ungual -
± 15
23
Second fL 55
54 ± 65 69
_
metatarsal < Wp
8-8
-
[Wd 9
9 13
-
Phalanx I -
25
29
II -
± 19
21
ungual -
22
-
Third CL, 62-5
63 ± 70 77
_
metatarsal < Wp 8
7'5 9
-
[Wd 1 1 -5
14 J5
-
Mw
5'5
8
21-5
10-5
14
9
12
17
± 4O
60
79
72
43
64
65
76
87
14
21
28
27
Manus
Ri96
R2OO
Rig6
R
R
46
± 56
13
10
12
8
13
15
6
29
—
8
-
-
+ 8
66
± 83
21
12
-
II
15
19
II
28
_
12
—
—
8-5
84
106
24
IO
15
9'5
18
22
8-5
ISLE OF WIGHT, ENGLAND 15
TABLE III (cont.)
Manus
R5830 RsSjo R2466 SM4i2y Rig6 Rig6 Raoo Rig6
L R L R L R R
Phalanx I - 25 28 25 10
II - 19 23 21 7
III - 16 5
ungual - ±23 app. 8
Fourth TL 55-5 53 ± 59 72 69 ± 90 15
metatarsal-^ Wp 99 13 15 7
[_Wd 9-5 9 ±10 14 14 20 6
Phalanx I - ± 17 19 18 5
II - 15 15 i? 3'5
HI - 13 14
IV - 12 12 12 ?
ungual - 17
Fifth f"L 23 24 35 10
metatarsal< Wp 6 9 8 6-5
IWd 3 5 5
III. THE HYPSILOPHODON BED
a) Stratigraphy
Casey (1963) showed that the onset of the Cretaceous period in Southern England
is indicated by the marine invasion that formed the Cinder Bed at the base of the
Durlston Beds in the Middle Purbeck Series. The rest of the Durlston Beds and the
succeeding Wealden Series consist mainly of lagoon and deltaic deposits. The
Lower Greensand, Gault and Upper Greensand beds are marine and represent the
remainder of the Lower Cretaceous in this region (B.M. (N.H.) Handbook 1962,
Hughes 1958), although Kirkaldy (1939, 1963) has included the last two in the Upper
Cretaceous with the Chalk. On the Isle of Wight there is no exposure of the equiva-
lents of the Hastings Beds of the Weald but only of the younger beds of the Weald
Clay, here represented by the Weald Marls with the overlying Shales. Remains of
Hypsilophodon, which occur next to the contact between the Marls and the Shales,
have been found only in Brightstone ( = Brixton) Bay, although this contact is also
exposed in the cliffs of Compton Bay and Sandown Bay (White 1921). The absence
of ostracods in the Marls and the lower part of the Shales makes it difficult to deter-
mine accurately the age of the Hypsilophodon Bed. It is probably Barremian (Allen
I955» B.M. (N.H.) Handbook 1962, Hughes 1958) but it might possibly be Early
Aptian (Hughes 1958) (see Text-fig 64).
The Hypsilophodon Bed is exposed in the cliff at beach level about 100 yd west of
Cowleaze Chine and rises in the cliff to end about f mile further west just beyond
Barnes High (White 1921, fig. ib, c ; Chatwin 1960, fig. ijb, c). A detailed succes-
sion of these marls and shales was given by Strahan (1889) who gave two descending
16 THE WEALDEN HYPSILOPHODON
sections of the beds at the junction region. He noted that the first (page 13),
between Cowleaze and Barnes Chine, was taken from various points in the cliffs :
«
Grey and black shales, the upper part interlaminated with
much sand in Cowleaze Chine ; a band crowded with Paludina
and Unio near the top, and another with Cyrena and Paludina
near the bottom 19' o"
White sand and clay, with lignite 2' 6"
Current-bedded white rock 2' 6"
Reddish-blue sand and clay, with bone fragments (Hypsilo-
phodon Bed) 3' o"
Red and variegated marls 44' o"
i
while the second (pages 14-16), from Atherfield to near Brook, gave the succession
at Cowleaze Chine :
•
'. . . about 144' . . .
Blue shales, with Unio and Paludina in the top, and Cyrena
Wealden
shales
and Paludina near the bottom 19' o"
White sand and clay 2' 6"
White rock 2' 6"
Red sand, with bones (Hypsilophodon Bed) 3' o"
Wealden ( Red and mottled marls, rocky and ripple-marked at the
marls \ top 44' o"
. . . about 510' . . .'
Judging on the lithology of these localities today, Strahan interchanged the two
sections - it will be noted that ' sand in Cowleaze Chine ' is mentioned in the section
which purports to relate to the cliff-section rather than to the beds at Cowleaze
Chine.
White (1921 : 16) noted that near Cowleaze Chine the white rock 'is a pale,
calcareous, silty stone, indistinctly shaly in places, and having an uneven base [see
Galton 1967, fig. 3A]. It contains Unio and water-worn bones'. The articulated
material found by Dr P. L. Robinson was in this shaly portion as well as in the
Hypsilophodon Bed below. Hooley, as noted by White (1921), found remains of
Hypsilophodon in the Marls a little below the Hypsilophodon Bed but not in the
Shales above.
White (1921 : 16) reproduced the second succession of Strahan (1889) and noted
that the Hypsilophodon Bed, although included with the shales, ' is lithologically and
stratigraphically more nearly allied to the marls'. As noted by Hulke (1882), the
Hypsilophodon Bed is extremely variable, even within the space of a few yards.
This is certainly true of the first hundred metres exposed in the cliff near Cowleaze
Chine. Here the bed consists of reddish-blue marls which are indistinguishable
from the Marls below. In the lower part of the Bed there are, in addition, several
ISLE OF WIGHT, ENGLAND 17
rocky bands of varying thickness which also occur near the top of the Marls (see
Galton 1967, figs. 36, C). About 160 m west of Cowleaze Chine there are well-
developed desiccation cracks in the marls (see Galton 1967, fig. 3Q. These cracks,
which are about 45 cm deep and 4 cm wide, are filled with sand continuous with that
of the overlying rocky band. It is difficult to determine whether this band is at the
top of the Marls or at the base of the Hypsilophodon Bed.
b) Hypsilophodon localities
Lydekkcr (1888) listed specimens of Hypsilophodon and in each instance the
locality, where given, was Cowleaze Chine. Swinton (19366 : 213) stated that ' almost
every specimen comes from Cowleaze Chine ' while, in connection with the two skele-
tons from the Hooley Collection, he stated (1936 : 555) that ' these two specimens,
like the type, are from the Wealden of Cowleaze Chine'. The Hypsilophodon Bed
where it crosses the mouth of Cowleaze Chine is buried underneath 12 ft of shingle.
If all the specimens actually came from the Chine then this productive site is now
very rarely accessible.
Owen (1855 : 2) stated that 28707 ' was discovered . . . about one hundred yards
west of Cowleaze Chine . . . the mass of Wealden stone . . . was broken into two parts
in its extraction from the bed'. Owen (1874 : 12, 13) quoted trom a letter written
by Fox in 1870 as follows (specimen numbers have been added) : 'This jaw [RiSg]
was found within a yard ot the skull [Rj-97 - the holotype]. They were both in a
mass of mud that had slided down from the cliff . . .', and '. . . you will find one very
small tooth [Rigi], quite perfect, that came out of this slab [Rigo] in dressing.
This slab [Rigo] was found in the fallen cliff, about 150 yards east of Barnes High.
. . . The skull [Ri97 - holotype] and broken jaw [Ri8g] were found about 60 yards
further eastward.' All these specimens were listed by Lydekker (1888) as from
Cowleaze Chine, whereas the actual site is at the opposite end of the bed, a little
over half a mile further west. Consequently the entry ' Cowleaze Chine ' is equiva-
lent to Hypsilophodon Bed ; this is all the data we have for specimens Ri92-Ri96
and R200 (Fox MS).
Hulke (MS) gave nearly all his localities as near Cowleaze Chine and exact details
were given only for R2466-R2476 which was found about 100 yd west of the Chine
(not the west end of the bed as stated by Hulke, 1874 : 18). In a memorandum
dated Oct. 1894, Hulke (MS, opposite find no. 260) wrote that ' I do not suppose the
Cowleaze end of this bed richer than the other parts of it, but its waste is greater and
fresh exposures are frequent '. The locality for R5829 and R5830 was near Cowleaze
Chine and the two recent finds of Hypsilophodon were both about 100 m west of
the Chine. Consequently more material may be found in the productive region
about 100 m west of the Chine.
c) Fauna
The Wealden of the Isle of Wight is famous for its dinosaurs but most of these are
represented by very fragmentary remains (for details see Swinton 19366). Apart
from the Hypsilophodon material, only two other reasonably complete skeletons have
18 THE WEALDEN H YPSILOPHODON
been found - those of Iguanodon atherfieldensis and Polacanthus foxii. Both repre-
sent large animals (about 5 m) whose cadavers were probably carried some distance
by water. The fragmentary and broken nature of the other dinosaurian remains
indicates that they were transported quite a long distance.
In marked contrast to this is the Hypsilophodon Bed, from which well preserved
and naturally articulated bones representing 20 individuals of this relatively small
dinosaur have been found. Three of these (Rig6, R582Q, R583O) are reasonably
complete skeletons. The incomplete nature of the remainder reflects faults of dis-
covery rather than of preservation because, in most instances, the edges of the
blocks cut across articulated bones. The skeleton of Rig6 is almost complete and
nearly all the bones were in natural articulation. It is unlikely that this individual
was carried very far, if at all, from where it died. The same is true of the two skulls
of young individuals (Ri97, R2477) in which the fragile bones are excellently pre-
served and only slightly disarticulated. In a few instances (RIQ6, R2477, U.C.L.)
two or three skeletons have been preserved very close to each other in the same small
block.
The ' fauna ' represented in the Hypsilophodon Bed is very restricted. Apart from
Hypsilophodon, Hulke (1882 : 1036) recorded the presence of ' a small scuted crocodile
(Goniopholisl} and a chelonian (Trionyx?)'. He also noted that neither Fox nor
he had found any remains of Iguanodon mantelli in this bed. In the Hooley collec-
tion there is a cervical vertebra that is probably Goniopholis and a phalanx that might
be from Iguanodon, but it is not certain that these came from the Hypsilophodon Bed.
The same is true of the proximal end of a small femur, possibly of Iguanodon, which
is catalogued with several odd femora of Hypsilophodon (Ri7o). The coelurosaur
Calamospondylus foxi may not have come from the Hypsilophodon Bed, because the
tibia is not listed as such by Fox (MS). Why Hypsilophodon, which is represented
by such excellent material, is the only dinosaur found in the Bed is a mystery. This,
however, is certainly the case, because Fox, Hulke and Hooley collected much
material from this Bed (full list in Galton 1967), all referable to Hypsilophodon.
IV. OSTEOLOGY OF HYPSILOPHODON FOXII
Order ORNITHISCHIA
Suborder ORNITHOPODA
Family HYPSILOPHODONTIDAE DoUo 1882 (page 175)
Genus HYPSILOPHODON Huxley 1869 (page 3)
EMENDED DIAGNOSIS. Five premaxillary teeth separated by step from maxillary
row with 10 or ii teeth, 13 or 14 on dentary ; enamelled medial surface of a dentary
tooth has a strong central ridge that is absent on the lateral surface of a maxillary
tooth. Narial openings completely separated by anterior process of premaxillae ;
large antorbital recess or depression plus row of large foramina in maxilla ; jugal does
not contact quadrate ; large fenestrated quadrate jugal borders lower temporal
opening. Five or six sacral ribs, the additional one borne on the anterior part of
the first sacral vertebra. Scapula same length as humerus ; obturator process on
ISLE OF WIGHT, ENGLAND 19
middle of ischium. Femur with following combination of characters : fourth
trochanter on proximal half, lesser trochanter triangular in cross-section with a
shallow cleft separating it from the greater trochanter, practically no anterior
condylar groove and posteriorly outer condyle almost as large as inner. The type-
species, H. foxii, is the only species known.
HOLOTYPE. British Museum (Natural History) No. RiQy.
PARATYPE. British Museum (Natural History) No. 28707.
Huxley read his paper on Hypsilophodon on 10 November 1869 ; this was published
in 1870 and citations are given as Hypsilophodon Huxley 1870. However, later
authors have overlooked a summary of this paper published in 1869 ; the year of
publication is confirmed by a reference in abstract in the Proceedings of the Geological
Society No. 205 p. 4 to the papers which were to be given at the next meeting on
24 November 1869. This summary provides an adequate diagnosis of Hypsilophodon
foxii which is certainly more detailed than that given by Boulenger (1881) for
Iguanodon bernissartensis.
Specimens used for osteology and reconstructions
The individual skull bones of R2477 were stuck together with Carbowax (poly-
ethylene glycol 4000) and their spatial relationships are maintained in all the figures
of this specimen. The description of the skull is mostly based on this specimen as is
the reconstruction of the complete skull (Text-fig. 3). Certain details are from other
specimens : the anterior end of the premaxilla is from RigG, the premaxillary teeth
and the quadratojugal are from Ri97, the supraorbital is from Ri94 and Ri97 and
the predentary is from R247O. The mandibular ramus is based on Rig6 with supple-
mentary details from specimen Ri92, Ri97, R2470, R2477 and R84i8. The restored
lengths of the dentary and of its tooth row are probably not absolutely accurate
because the jaw is reconstructed from several incomplete specimens of different size.
The size of the predentary is approximate because the only specimen is of a small
individual. The spatial relationship between the articular head of the quadrate and
the end of the tooth row is accurate as this is based on the lower jaw of R2477. The
jugal is adapted from Ri97 and R2477 but the resulting quadratojugal (Text-fig. 3)
is proportionally rather longer ventrally than that of Ri97 (Text-fig. 2). In the
reconstruction the basipterygoid processes are separated by about 7 mm from their
original contact with the pterygoid. This indicates that the braincase should be
situated some 7 mm more anteroventrally. However, if the parietal, squamosal
and quadrate are also moved by the same amount the posterior teeth of the lower jaw
fail to engage the corresponding teeth of the maxilla.
The reconstruction of the postcranial skeleton (Text-fig. 62) and the osteology of
the individual elements (apart from the femur, tibia and fibula, for which R5830 is
used) are based on the nearly complete skeleton of Rig6 and the tail Rig6a.
Individual variations exhibited by specimens other than R2477, Rig6 and R5830
are noted after the description of the element concerned. In the Text-figures all bones
are drawn from the left side unless otherwise stated.
THE WEALDEN HY PS ILOPHODON
N
PMX
ISLE OF WIGHT, ENGLAND
21
PF
FIG. 3. Hypsilophodonfoxii. Skull reconstruction, mainly R2477 x i.
see below ; for specimens used see page 19.
For abbreviations
a) The skull and lower jaw
i) INDIVIDUAL BONES
Supraoccipital (SO). This bone forms the dorsal boundary of the foramen magnum.
The posterior surface (Text-fig. 8) which is inclined forwards at an angle of about
55 degrees to the skull axis (Text-fig. 5 A), is flat ventrally but bears a median ridge
dorsally. The surface on either side of this ridge is concave and sweeps obliquely
outwards, forming a dorso-lateral corner with the lateral part of the bone. This forms
part of the side-wall of the braincase and is concave antero-posteriorly and to a lesser
extent dorso-ventrally (Text-fig. 5C). Apart from the median ridge the dorsal and
medial parts of the bone are quite thin. The ventro-lateral part, especially more
posteriorly, is very thick. The ventral surface is gently convex antero-posteriorly
but strongly concave transversely.
FIG. 2. Hypsilophodonfoxii. Holotype, Rigy. Skull x i. A, left side
C, ventral view. Abbreviations used in Text-figs. 2-16
parasphenoid
prearticular
predentary
prefrontal
premaxilla
postorbital
prootic
pterygoid
quadrate
B, right side
A
ART
BO
BSP
CB
CO
D
ECT
EO
angular
articular
basioccipital
basisphenoid
ceratobranchial
coronoid
dentary
ectopterygoid
exoccipital
F
J
L
LSP
MX
N
OP
P
PAL
frontal
jugal
lachrymal
laterosphenoid
maxilla
nasal
opisthotic
parietal
palatine
PSP
PA
PD
PF
PMX
PO
PRO
PT
Q
QJ
quadrate ju gal
sc.pl.
sclerotic plate
SPL
splenial
SQ
squamosal
SO
Supraoccipital
SOB
supraorbital
SA
surangular
V
vomer
22 THE WEALDEN H YPSILOPH ODON
The end part of the dorso-lateral corner has suture markings (Text-fig. 56, PI. 2,
fig. i) while anteriorly there is a lateral groove that becomes wider as it runs diago-
nally across the side-wall. From the central part of this groove a ventral groove arises
that passes through the floor of the lateral groove. The vena capitis dorsalis probably
ran in the anterior part of the lateral groove and then into the ventral groove.
Anteriorly it was bounded laterally by the parietal that enclosed the dorsal part of
the supraoccipital (Text-fig. 5 A) and fitted against the side-wall adjacent to the
groove. In passing ventrally the vena capitis dorsalis passed medially to the edge
of the parietal. More posteriorly the edge of the parietal fitted into the tapering
posterior part of the lateral groove and on to the sutural surface of the dorso-lateral
corner. The opisthotic is sutured to the obliquely truncated postero-lateral corner
of the supraoccipital which has a large and almost square sutural surface. The
prootic is sutured to a triangular surface on the ventral edge and, like the surface
for the opisthotic (both visible in R84i8), it has well-developed sutural ridges. The
sutural junction with the prootic is excavated medially to form a large tapering
tunnel, the fossa subarcuata (Text-fig. 96, C), which was probably for the floccular
lobe.
Exoccipital (EO). The suture between the exoccipital and the opisthotic is not
visible in R2477. In R84i8 on the medial surface there is a sutural line (Text-fig.
96) but unfortunately this cannot be followed on to the other surfaces. The ex-
occipital forms the ventro-lateral border of the foramen magnum while the round
posterior surface forms part of the occipital condyle. The ventral surface has strong
sutural ridges for the basioccipital.
Basiocdpital (BO). This forms most of the sub-spherical occipital condyle whose
smooth articular surface is well developed ventrally (Text-fig. 6A) as well as posteriorly
(Text-fig. 8). Anteriorly from the condyle there is a tapering median ventral ridge
(Text-fig. 6A) with well-developed insertion markings. In R583O the anterior sur-
face, which is more or less vertical, has two subcircular areas for the buttress 01 the
basisphenoid. On each side there are two obliquely inclined lateral surfaces, with
well-developed sutural ridges, which are set at an angle of about 135 degrees to each
other. The smaller anterior surface is for the basisphenoid while the larger surface
is for the opisthotic and also, more posteriorly, for the exoccipital.
Opisthotic (OP). This forms the lateral wall of the foramen magnum (Text-figs.
46, 9 A). The paroccipital processes of R2477 are missing but have been restored
with reference to specimens Ri94 and Rig6. The proximal end of the bone is thick,
roughly triangular in cross-section, with a ventrally directed part that continues
the side-wall of the braincase (Text-fig. 9 A). The bone tapers laterally, with the
anterior edge gradually disappearing, to form a flattened paroccipital process (Text-
fig. gA). The anterior edge is flat, forming a sutural surface for the prootic. Dorsal
to this the surface of the proximal half is laterally concave as it is ventrally where this
curve is much more strongly developed. The ventral edge is thick and rounded
proximally but becomes thinner laterally. The dorsal edge is thin and moderately
sharp along all its length.
ISLE OF WIGHT, ENGLAND
PF
N
PMX
BO
B
PMX
PRO SO
N
cav
bptp.
FIG. 4. Hypsilophodon foxii. Skull R2477 x i. A, lateral view, compare with PI i,
figs. 3, 4 ; B, medial view, as A but with lateral bones of the left side removed, compare
with PI. 2, fig. 2. Abbreviations : bpt p., basipterygoid process ; c, foramen for internal
carotid artery ; cav, cavity in the premaxilla ; o, bony element ; v. cap. d., vena capitis
dorsalis ; V, trigeminal foramen; Vn, facial foramen. For other abbreviations see
page 21.
THE WEALDEN HYPSI LOPHODON
ISLE OF WIGHT, ENGLAND
B
MX
PMX
MX
ant.cav.
SQ
5cm
ant.cav.
MX
cav
PMX
PAL
PSP PRO
OP
FIG. 5. Hypsilophodon foxii. Skull R2477. x i. A, medial view as Text-fig. 46 but
with braincase and palatine sectioned, nasals and vomer removed, premaxilla, squamosal
and quadrate displaced ; B, dorsal view, compare with PL i, fig. i ; C, dorsal view of the
palate and braincase, as B but with bones of the skull roof and most of the left side
removed, premaxillae, maxilla and jugal sectioned, compare with PI. 2, fig. i. Abbrevia-
tions : ant. cav., antorbital cavity or fossa ; bpt.p., basipterygoid process ; cav., cavity
in premaxilla ; s, sella turcica ; V, trigeminal foramen. For other abbreviations see
page 21.
26 THE WEALDEN H YPSILOPHODON
The ventral surface of the braincase side-wall forms a rectangular surface with
well-developed sutural ridges (visible in R84i8) for the basioccipital. The anterior
part of this wall forms an irregularly shaped sutural surface with well-developed
sutural ridges for the prootic. The fenestra ovalis, middle ear cavity, internal
auditory meatus and the jugular foramen are situated between the opisthotic and
the prootic (Text-fig. 9). The tapering postero-dorsal part of the prootic also
sutures to the flat-topped anterior edge of the opisthotic. The surface for the
supraoccipital (Text-fig. 96) has strong sutural ridges. The adjacent dorsal edge
contacted the squamosal which is overlapped by the paroccipital process (Text-
fig. 8).
Prootic (PRO). This is an irregularly shaped bone (Text-fig. 9) which forms part
of the lateral wall of the braincase. The dorsal part of the bone continues the dorso-
ventrally convex curve from the adjacent laterosphenoid (Text-fig. 46). This
curve becomes more acute passing posteriorly where the prootic tapers to a point
which overlaps the paroccipital process (Text-fig. gA). The ventral part is concave
dorso-ventrally but this curve is complicated by three foramina (Text-fig. 9 A).
Posterior and ventral to the foramen ovale (V) the surface slopes gently away from
the foramen but dorsally the slope is steeper, as it is around the facial foramen (VII),
while the posterior edge is vertical. The sides of VII spiral slightly so that the steeper
anterior surface forms a step above the ventral edge. This step is continued antero-
ventrally where it becomes more pronounced as there is a well-developed depression
at this point. Dorsally the depression is overhung by a thin and sharp edge. The
prootic is sutured to the laterosphenoid, supraoccipital, opisthotic and basioccipital.
Basisphenoid (BSP). This median bone forms a thick floor to the anterior part of
the braincase (Text-fig. 5 A). In ventral view (Text-fig. 6A) the posterior part
forms two buttresses which abut against the basioccipital and slightly overlap this
vertical suture. The two buttresses, which are separated by a median depression,
taper anteriorly with the lateral edges becoming thinner and sharper. The diverging
pterygoid processes have, on the anterior part of their base, a well-developed depres-
sion which is continued on to the base of the parasphenoid. Adjacent to this
depression the anterior edge is thin and sharp but more distally it is much thicker
and rounded.
In lateral view (Text-fig. 46) the distal part of the basipterygoid process has a
rough surface which, with its continuation on to the rounded anterior edge and a
smaller but similar surface on the medial surface, articulated with the pterygoid.
The posterior edge of the process is thick and rounded and it continues postero-
dorsally across the side of the basisphenoid. There is a deep excavation of the side
of the bone postero- ventral to this edge so that there is only a thin median sheet.
This thickens considerably postero-laterally and the excavation becomes pro-
gressively shallower. The ventral edge is formed by the buttress which is latero-
ventrally flattened. The excavation and its bordering diagonal edge are continued
on to the adjacent surface of the prootic. Anterior to this diagonal edge the surface
of the basisphenoid is rough textured. The dorso-median part of the bone is deeply
excavated to form the pituitary fossa (Text-figs. 5A, C) from which paired foramina
ISLE OF WIGHT, ENGLAND 27
for the carotid arteries pass postero-laterally, one on each side of the thin median
sheet (Text-fig. 6A).
Parasphenoid (PSP). This arises from the basal region of the basipterygoid pro-
cesses, anterior to the pituitary fossa, and runs forward to bisect the posterior part
of the palatal vacuity (Text-fig. 6A). This tapering process is triangular in cross-
section, with a concave dorsal surface, and the edges are thin and sharp. Its anterior
limit cannot be determined in R2477.
Later o sphenoid (LSP). The lateral surface (Text-fig. 46) is gently concave antero-
posteriorly and convex dorso-ventrally ; there is a well-developed depression on the
ventral part running antero-dorsally from the foramen ovale (V). The dorsal end
of the bone is expanded laterally (Text-fig. 76) to form a head, the rounded dorsal
surface of which fits into a cavity formed by the frontal and postorbital (Text-fig.
6B). The anterior surface is flat and tapers ventrally (Text-fig. 76). The medial
surface (Text-fig. 5A) is dorso-ventrally concave while antero-posteriorly it consists
of two very gently concave areas separated by a very gently convex ridge.
The dorsal surface for the parietal is thin and flat with a few minor ridges. The
thin dorsal part of the posterior edge is gently rounded for the supraoccipital.
More ventrally this edge is much thicker and formed the sutural surface for the pro-
otic. The suture is obliquely inclined with the laterosphenoid overlapping the prootic
(Text-figs. gA, C). Just above the foramen ovale (Text-fig. gA) there is a notch in
the margin to receive a process of the prootic. Ventrally the second surface for the
prootic is vertical, flat and triangular in outline.
Orbitosphenoid. This is not represented by the ossified plate present in Parksosaurus
(see Galton, in press) and Camptosaurus (see Gilmore 1909). Anteriorly on the medial
part of the laterosphenoid head there is a slight step, continuous with the straight
antero-medial edge (Text-figs. 6B, 76), while on the adjacent edge of the frontal
there is a groove (Text-fig. 6B). These probably represent two of the contact
surfaces of the orbitosphenoid which may not have been ossified.
Premaxilla (PMX). Each premaxilla has an anterior and a posterior process
(Text-fig. 4A) while medially there is a ventral sheet (Text-fig. 6A). The narial
opening is bordered by the anterior process which, together with its fellow on the
other side, wedges between the nasals (Text-figs. 5B, 6B) so that they overlap very
slightly. This process, triangular in cross-section, has a lateral edge which continues
on to the main body of the bone (Text-fig. 4A) . The surface in front of this edge is
covered with large knobs while more ventrally there are two foramina (f 2, f 3, Text-fig.
4A) . The rough and knobbly anterior end of the premaxilla was probably covered
by horn to form a beak. Behind this edge the surface is concave and it is more
obliquely inclined on the process, at the base of which there is another foramen (fx).
The posterior half of the lateral surface is gently convex antero-posteriorly (Text-fig.
56) and concave dorso-ventrally (Text-fig. 7A). Anteriorly the posterior process is
gently rounded while posteriorly the edge is thin and sharp. More ventrally the
bone is thicker with a well rounded edge (Text-fig. 7A).
28
THE WEALDEN HYPSI LOPHODON
MX
PMX
cav
5cm
bpt.p. LSP
B
PMX
PF
FIG. 6. Hypsilophodon foxii. Skull R247y, x i. A, palatal view, compare with PI. i,
fig. 2 ; B, ventral view of the skull roof. Abbreviations : c, foramen for internal carotid
artery ; cav., cavity in the premaxillae ; bpt. p., basipterygoid process. For other
abbreviations see page 21.
ISLE OF WIGHT, ENGLAND
LSP
B
FIG. 7. Hypsilophodonfoxii. Skull R2477, x i. A, anterior view ; B, anterior view with
skull sectioned through the middle of the orbits with the frontal, orbital and palatal bones
of the right side removed and the quadrate displaced. Paroccipital process restored
from RiQ4. Abbreviations : bpt. p., basipterygoid process ; par. p., paroccipital process ;
s, sella turcica ; x, remnant of post- temporal fenestra ; V, trigeminal foramen ; VII,
facial foramen. For other abbreviations see page 21.
30 THE WEALDEN HYPSI LOPHODON
The ventral surface (Text-fig. 6A) is transversely concave with five marginal
thecodont teeth, each with a foramen medial to it. In R5830 and R8367 the median
surface of the tapering ventral sheet and of the anterior process form one continuous
flat sutural surface for the other premaxilla. In RiQ7 and R2477 (Text-fig. 46)
these two surfaces are separated by a large depression which communicates with the
exterior ventrally (Text-fig. 6A). Above the tapering ventral sheet there is a large
channel which tapers in the opposite direction (Text-fig. 5A) with longitudinal ridges.
This channel receives the anterior process of the maxilla and also the median vomer
more postero- ventrally (Text-figs. 46, 5C) . Above this channel the surface is slightly
concave. In R2477 the dorsal part of the posterior process sutures medially with a
flange on the nasal (Text-figs. 4A, B). The sutural union is delimited by a slight
edge which then curves antero-ventrally. In RiQ7 the posterior process contacts
the maxilla all along its posterior border (Text-fig. 2 A).
Maxilla (MX) . The maxilla consists of a thick rod with ten or eleven tooth-sockets
(Swinton 1936, fig. i). On the medial surface (Text-fig. 5 A) there is a longitudinal
ridge, convex transversely, which is continued anteriorly as a process. This pro-
cess, triangular in cross-section, is slightly off-set from the rest of the ridge (Text-fig.
56) and it bears strong sutural ridges. The two maxillary processes and that of the
vomer fit tightly into a cavity enclosed by the premaxillae (Text-figs. 46, 5 A, C).
The limit of overlap on the lateral surface is indicated by an edge that is a con-
tinuation of the sharp edge at the anterior end of the tooth row.
Above the main tooth-bearing region the maxilla consists of two thin fenestrated
sheets which enclose the antorbital fossa (Text-figs. 4, 5, 6oB, C). The lateral sheet
arises from the side of the main body that it overhangs (Text-fig. 6A). This sheet
has several foramina of varying size (Text-fig. 4A) while, more dorsally, it forms the
anterior and ventral margins of the antorbital fenestra. The medial sheet forms a
thin dorsal edge to the main body immediately above the roots of the teeth. This
sheet has a much shallower vertical curve than the lateral sheet that it joins in the
middle of the antero-dorsal part (in front of the antorbital fenestra, Text-fig. 5 A).
The more dorsal part of the medial sheet is overlapped by the thin sheet of the
lachrymal (Text-fig. 5 A) with which it forms the medial wall of the antorbital fenestra
(Text-fig. 4A) and fossa. There is a large fenestra anteriorly in the medial sheet of
the maxilla, while posteriorly, where it tapers to nothing, it borders another large
fenestra with the lachrymal (Text-fig. 5 A). The posterior margin of the latter is
formed partly by the palatine bar and possibly also by the maxilla below. Posterior
to this bar the antorbital fossa opens dorsally and posteriorly (Text-fig. 5) with the
sides, especially medially, becoming progressively shallower (Text-fig. 5 A). The
medial wall of this part is formed by the main body of the maxilla with the thin
lateral sheet curving dorso-laterally. The jugal forms an inwardly projecting ledge
which roofs the more lateral parts of the fossa (Text-figs. 56, C). The posterior end
of the maxilla is sharp-edged and straight, making an angle of about 45 degrees with
the vertical.
In R2477 the lateral sheet contacts the premaxilla only dorsally (Text-fig. 4A)
and there is a narrow vacuity. The lateral sheet is extremely thin yet it has a
perfect edge and it is the same on both sides. Consequently the thin anterior edge
ISLE OF WIGHT, ENGLAND 31
was not completely ossified in R2477 ; this, however, must be an individual variation
because in Ri97 the lateral sheet is proportionately larger with an extra foramen and
is completely overlapped by the premaxilla (Text-fig. 2). The lachrymal overlaps
the medial surface of the medial sheet while posteriorly it contacts the thin edge of
the lateral sheet in R2477 (Text-fig. 4A), though not in Ri97 (Text-fig. 2 A). Ventral
to the bridging bar of the palatine there is part of the medial sheet of the maxilla
which probably also touched the lachrymal. The main body of the palatine is
sutured diagonally on to the medial surface of the maxilla (Text-figs. 46, 5A, C) with
fine parallel suture ridges postero-ventrally but the surface is more irregular antero-
posteriorly near the bar. The lateral sheet of the maxilla forms an overlapping
suture with the jugal in R2477 (Text-fig. 4A) but in RiQ7 (Text-fig. 2 A) only the
edge fits against the jugal more anteriorly. The jugal also sutures to the lateral
part of the wedge-shaped posterior end of the maxilla which, with the medially
directed process it bears (Text-fig. 56), fits into a groove in the ectopterygoid.
Nasal (N). The nasals are rather thin and one slightly overlaps the other. The
lateral margin of the nasal is turned downwards anteriorly to form a vertical sheet,
the lower part of which is overlapped by the posterior process of the premaxilla.
The tapering posterior part of the nasal overlaps the frontal while more laterally it
is overlapped to a progressively greater extent by the prefrontal (Text-figs. 56, 6B).
This is greatest near the lateral edge where the prefrontal fits into a groove in the
side of the nasal. This groove continues on to the latero-ventral edge of the nasal
where it receives the lachrymal.
Parietal (P). In dorsal view (Text-fig. 5B) the anterior part of the single parietal
is flat but the sides are obliquely concave and transversely constricted with a thin
median edge. In anterior or posterior view (Text-fig. 8) there are two postero-
lateral wings which are twisted along their long axis ; the axis is somewhat obliquely
inclined. In ventral view the parietal is laterally convex and transversely concave,
with the sides becoming progressively steeper more posteriorly (Text-fig. 6B).
The parietal overlaps the frontals anteriorly ; the slightly concave suture surface
bears strong ridges which become weaker laterally (Text-fig. 76). The median
process of the parietal fits between the frontals and is itself overlapped slightly
(Text-figs. 5A, 6B). The antero-lateral corner forms a vertical facet with strong
sutural ridges for the postorbital (Text-fig. 46). The anterior part of the ventral
edge is flat, then grooved (the laterosphenoid fitted against this region) while more
posteriorly this edge is sharp (Text-fig. 6B). The parietal enclosed the dorsal part
of the supraoccipital (Text-fig. 5A).
Frontal (F). The frontals are elongate and form most of the dorsal margin of the
orbits. In dorsal view (Text-fig. 56) the central part of each bone is slightly concave
transversely. The orbital rim, which bears well-developed insertion markings, is
quite thin because the ventral surface above the orbits is obliquely concave (Text-fig.
A4) ; the plane of the orbital circle makes an angle of about 45 degrees with the mid-
line (Text-fig. 76). This obliquely concave surface forms a very prominent and
sharp-edged ridge ventrally (Text-fig. 6B) where it meets another concave surface,
THE WEALDEN HYPSI LOPHODON
LSP F P0
FIG. 8. Hypsilophodon foxii. Skull R2477, x i. Abbreviations: bpt. p., basipterygoid
process; par. p., paroccipital process ; x, remnant of post-temporal fenestra. For other
abbreviations see page 21.
the ' transverse ' plane of which varies so that the curve is always perpendicular to
that of the orbital surface. This medial curved surface is more strongly concave
anteriorly.
The sutural markings on the thin anterior part of the edge between the frontals
are very slight but on the thick central part they are well developed, consisting of a
cone- within-cone pattern (Text-fig. 5 A). On the thinner posterior part they are
deeper, more vertical but less regular. The frontals are sutured to the parietal, the
prefrontals and the squamosals. Postero-laterally on the ventral surface there is a
slight depression which, together with the larger one on the postorbital, receives the
head of the laterosphenoid (Text-fig. 6B) . The postorbital itself sutures on to a well-
developed spike (Text-fig. 76) of the frontal.
Jugal (J). The outer orbital edge of the jugal is gently rounded and medial to this
the jugal floors the ventral part of the orbit (Text-fig. 56). Anteriorly this floor is
obliquely inclined, facing medially and somewhat postero-dorsally but posteriorly
the plane shifts until it faces anteriorly (Text-fig. 7A). The inner edge of this orbital
floor is rounded anteriorly but becomes very thin and sharp-edged more postero-
dorsally (Text-fig. 46) . The remainder of the j ugal is an extremely thin sheet of bone.
Anteriorly the jugal fits against the ventral edge of the thick part of the lachrymal.
The sutural relationships with the maxilla and lachrymal vary in RiQ7 (Text-fig. 2A)
and R2477 (Text-fig. 4A) . Posteriorly the jugal forms an ' M '-shaped suture with the
pointed ends of the maxilla and ectopterygoid (Text-fig. 6 A). The postero-dorsal
part of the jugal has an overlapping suture with the tapering end of the postorbital
(Text-fig. 4 A). The thin part of the jugal overlaps the quadrat oj ugal (Text-fig. 2 A).
ISLE OF WIGHT, ENGLAND 33
Quadratojugal (QJ). The sheet-like quadrate jugal is perforated by a relatively
large foramen (Text-fig. 2 A). The edge of this foramen and the ventral edge of the
bone are rounded while the dorsal and posterior edges are thinner and sharp. The
anterior edge is hidden by the overlapping jugal. Postero-dorsally the quadrato-
jugal is overlapped by the quadrate but more ventrally the position is reversed, with
the quadratojugal extending nearly to the mandibular condyle (Text-figs. 3, 4 A).
Quadrate (Q). From its rounded condylar region the main body of the quadrate
rises, twisting through 45 degrees, to form a head (Text-fig. 4A). This head, tri-
angular in cross-section, inserts in a socket in the squamosal ; its anterior (Text-fig.
76) and inner (Text-fig. 5A) surfaces are covered with markings of ligamentous
insertions. The main body of the quadrate and its pterygoid flange, set at about
70 degrees to one another, form the outer (Text-fig. 3) and the posterior (Text-fig.
7A) borders respectively of the lower temporal vacuity. The anterior and posterior
edges of the main body of the quadrate are thin and sharp but its shaft is thicker and
more rounded. For most of its height the pterygoid flange arises from the middle
of the main body but dorsally its origin migrates backwards and takes part in the
formation of the dorsal head of the quadrate (Text-figs. 5 A, 8). A process of the
squamosal fits between these two sheets of the quadrate in this region. The junction
region between these two sheets is laterally concave along most of its length posteriorly
(Text-fig. 8) and also anteriorly (Text-fig. 76), but here the angle is more acute.
The antero-medial face of the shaft is slightly concave dorso-ventrally (Text-fig. 76)
with well-developed pore markings.
There is very extensive overlap between the pterygoid flange and the alar process
of the pterygoid. Neither of these two sheets is complete, but the shape of the
missing parts of each is outlined on the more basal parts of the other. The quadrato-
jugal has an overlapping suture with the lateral sheet of the quadrate and the limits
of the suture are marked by an edge (Text-figs. 3, 4A).
Squamosal (SQ). This bone forms the postero-dorsal corner of the skull (Text-fig.
3), the lateral part of the occipital crest (Text-fig. 56) and the posterior portion of the
upper temporal bar. It is a roughly quadriradiate bone with rather unequally
developed processes. The external surface (Text-fig. 4 A) at the junction of the two
larger processes, which are anteriorly and medially directed, is strongly convex
while the inner surface (Text-fig. 76) is concave forming the latero-posterior wall of
the supratemporal fossa. Ventro-laterally there are two smaller processes which
border the deep socket for the head of the quadrate. The posterior process forms a
continuous sheet with the medial process and in posterior view (Text-fig. 8) the sur-
face passing laterally is basically gently convex and then concave but dorsally above
the socket there is a strongly convex part. In lateral view (Text-fig. 4 A) there is an
edge joining the lateral edge of the anterior process to the posterior edge of the pos-
terior process (Text-fig. 5B). In ventral view (Text-fig. 6B), the large anterior
concave area and the socket are separated by a wide bridge of bone, which shortly
tapers as it passes antero-laterally and the surface of which is concave in this direc-
tion. The edges of the bone are thin and sharp. The medial process overlaps the
34
THE WEALDEN H YPSILOPHODON
B
par. p.
ix,x, int.j.v.- for.l.p. & j.for.
par. p.
fos. sub.--""""^
for. I. p.
& j.for.
par. p.
f os. sub.
EO
(for. I. p.
ix.x.xi, int.i.vJ _
1& j.for.
FIG. g. Hypsilophodon foxii. Side-wall of braincase, composite : EO, exoccipital 1^8367 ;
LSP, laterosphenoid R2477 ; OP, opisthotic RiQ4, R2477 ; SO, supraoccipital R8366.
x 1-5 for R2477. A, ventro-lateral view ; B, dorso-medial view with supraoccipital
removed. C, as B but with supraoccipital sectioned. Abbreviations : f., foramen ;
fen. ov., fenestra ovalis ; for. 1. p., foramen lacerum posterius ; fos. sub., fossa subarcuata ;
int. aud. m., internal auditory meatus ; int. j. v., internal jugular vein ; j. for., jugular
foramen ; 1., lagenar recess ; par. p., paroccipital process ; p.t. f., remnant of post-
temporal fenestra ; so., surface for supraoccipital ; foramina for cranial nerves in Roman
numerals, other abbreviations see Fig. 60
ISLE OF WIGHT, ENGLAND 35
parietal anteriorly. The ventral edge of this process is sutured to the opisthotic
while the posterior process is overlapped by the paroccipital process (Text-figs. 76,
8). The anterior process is overlapped laterally by the posterior process of the post-
orbital.
Lachrymal (L). The main part forms the dorsal border of the antorbital fenestra
while the medial sheet forms an inner wall (Text-fig. 3). In lateral view (Text-fig. 3)
the main part is gently convex transversely and longitudinally. Ventrally it is
hollowed out to form a thin and sharp edge which overhaps the base of the medial
sheet. The plane of this sheet is at an angle to that of the main part so that they are
wider apart posteriorly. Here the lachrymal has a posterior surface (Text-fig. 56)
which forms part of the margin of the orbit. The lachrymal foramen is on this
surface and its duct follows the curved dorsal margin of the lachrymal in the junction
region (Text-figs. 6oC, D) . It opens at the pointed anterior end medial to the maxilla.
The sutural relationship with the maxilla and jugal varies in Ri97 (Text-fig. 2 A)
and R2477 (Text-fig. 4A). The end of the palatine bar sutures to the medial edge
of the lachrymal just anterior to the jugal (Text-fig. 56). Dorsal to this there is a
groove along the postero-medial edge of the lachrymal (Text-fig. 46) in which there
is still a small piece of bone. The original bone was a slender rod. The dorsal edge
of the lachrymal is sutured to the prefrontal and nasal ; this edge has a groove to
receive the prefrontal while more anteriorly its edge fits into a groove on the edge of
the nasal.
Prefrontal (PF). This bone forms the edge of the orbit and consists of two
tapering sheets ; the dorsal one (Text-fig. 5B) is gently convex antero-posteriorly
while the lateral one is concave (Text-fig. 4A) , obliquely inclined and slightly twisted
along its longitudinal axis. The medial surface (Text-fig. 5A) is concave but more
gently angled and the long edges are sharp. The prefrontal overlaps both the nasal
and the frontal (Text-figs. 56, 6B). The anterior edge fits into a groove on the dorsal
edge of the lachrymal. The lateral corner of the bone is thick with well-developed
suture pits and ridges for the supraorbital.
Supraorbital (SOB). The supraorbital is preserved in the right orbit of Ri97
(Text-fig. 2B) and there is one from RiQ4 (see Text-fig. 3). The shaft of the bone is
curved and tapers, with an oval cross-section and sharp edges, and is slightly twisted
along its longitudinal axis. Anteriorly there is a dorso-medial flange that is also
present in RiQ7 but there is no sutural area corresponding to it on the prefrontal of
R2477. There is a transversely concave area on the outside of the flange with a
slight ridge on the shaft. The dorso-lateral surface and the posterior part of the
inner surface are covered with fine surface markings. More proximally it is smooth
but with several slight ridges running diagonally across the shaft.
Postorbital (PO). This is a triradiate, sharp-edged bone forming the posterior wall
of the orbit and the anterior part of the upper temporal bar. The outer surface is
flat antero-posteriorly and curved transversely (Text-fig. 76). The slender and
tapering posterior and ventral processes (Text-fig. 56) are in the same plane. The
posterior process is thinner than the ventral, which latter has a medial ridge and is
36 THE WEALDEN HYPSI LOPHODON
triangular in cross-section (Text-fig. 6B). This ridge becomes thicker dorsally where
it forms the ventral part of the medial process (Text-fig. 6B). The medial process is
short but stout with a dorsal ridge (Text-fig. 56) which links a similar ridge on the
parietal to the dorsal edge of the posterior process. The surface behind this edge is
slightly concave and is continuous with the ventral surface with which it forms a
twisted plane (Text-figs. 56, 6B).
There is a very strong union between the medial process of the postorbital and the
adjacent bones. Ventrally the thick medial process has two large cavities, one
lateral and ventral to the other, which are partly separated by a thin dividing wall.
The dorso-medial cavity is for the large spike on the corner of the frontal (Text-fig.
76). This spike is bounded on all sides, though to a lesser extent ventrally, by the
postorbital which also overlaps the frontal with a small anterior flange (Text-figs.
56, 6B). The roof of the ventro-lateral cavity forms an oval depression (Text-fig.
6B) with the adjacent surface of the frontal. This depression, the side-walls of which
become deeper as they pass laterally, is for the large head of the laterosphenoid
(Text-fig. 7 A). Posteriorly there is a small sutural surface for the parietal. The
tapering end of the posterior process overlaps the anterior process of the squamosal
while the ventral process overlaps the jugal (Text-figs. 3, 4 A).
Pterygoid (PT). The triradiate pterygoid has long and thin alar processes to the
adjacent bones. Those for the palatine and ectopterygoid form a sheet (Text-fig.
6A) which is slightly concave antero-posteriorly. Approximately perpendicular to
this sheet, to which it is linked by a thickened connecting region, is the very broad
alar process for the quadrate (Text-figs. 46, 6A). In medial view (Text-fig. 46) the
quadrate process is concave dorso- ventrally apart from the obliquely convex antero-
dorsal corner. Ventrally there is a concave border delimited by an edge that runs
parallel to the ventral margin. The anterior part is thicker, covered with insertion
markings and has a centrally situated depression. This depression with the adjacent
small process receives the basipterygoid process of the basisphenoid (Text-figs. 56,
6A). The lateral surface of the quadrate process has a well-defined sutural area
(Text-fig. 4A) for the quadrate.
In ventral view (Text-fig. 6A) there is a well-defined corner on the centre of the
connecting region. The anterior edge of the connecting region is sharp but becomes
rounded at the base of the quadrate process (Text-fig. 76). The anterior part of the
palatine process is missing but the part of the palatine that was overlapped is visible
(Text-fig. 6A). The pterygoid overlaps the ectopterygoid ventrally with a broad
process which tapers to a point.
Ectopterygoid (ECT). The main part consists of a bar, triangular in cross-section,
which forms two equal halves at right angles to each other (Text-figs. 56, 6A, 76)
plus a medial flange (Text-fig. 56). The dorsal ridge on the anterior half of the
ectopterygoid is gently rounded with a convex surface in front of it (Text-fig. 56).
More medially and posteriorly this edge becomes thinner and sharper, with irregular
bumps, and the surface medial to it is concave. In the central region this surface
is large because it continues on to the medial flange (Text-fig. 56). The other edges
of the bone are thin and sharp. The lateral end of the ectopterygoid is strongly
ISLE OF WIGHT, ENGLAND
5cm
37
B
ART
m.c.
FIG. 10. Hypsilophodon foxii. Mandibular ramus, x i for Rig6 with details from Ri93,
Rigy and R2477. A, antero-lateral view ; B, dorsal view ; C, postero-medial view.
Abbreviations : d., surface for dentary ; m.c., Meckelian canal ; mid, midline ; pd,
surface for predentary ; q, surface for quadrate. For other abbreviations see page 21.
sutured to the jugal (Text-figs. 46, 5, 6A, 8). The antero- ventral surface of the
anterior half of the bone is excavated to form a deep groove for the sharp posterior
edge of the maxilla (Text-figs. 5, 6A, 76). The medial flange of the ectopterygoid is
sunk into the dorsal surfaces of the pterygoid (Text-fig. 56).
Palatine (PAL). The palatine consists of a broad base, sutured to the medial surface
of the maxilla (Text-figs. 46, 5 A, C), and bears a thin alar process from approximately
along the middle and perpendicular to the base (Text-figs. 5 A, C). Dorsally and
ventrally the surface of the palatine is continuous with the adjacent surface of the
maxilla (Text-figs. 5C, 6A). Anteriorly the palatine is much thicker and set at about
70 degrees to the maxilla. The lateral end of this thick part of the palatine forms a
bar, triangular in cross-section, which bridges the antorbital fossa to suture with the
medial surface of the lachrymal (Text-figs. 56, 56). The dorsal surface (Text-fig.
5C) in slightly convex longitudinally and slightly concave transversely, with this
THE WEALDEN HYPSILOPHO DON
B
1 cm
FIG. ii. Hypsilophodon foxii. Predentary R247O, x 1-5. A, anterior view ; B, lateral
view ; C, posterior view ; D, dorsal view ; E, ventral view. Abbreviation : d, surface
for dentary.
curve becoming stronger on the posterior part of the bone where the alar process is
slightly convex (Text-fig. 46). The thick anterior edge forms a surface, tapering
medially, which is convex dorso-ventrally and straight transversely except for the
medial part which is concave (Text-fig. 56). In medial view (Text-fig. 46) the bone
is gently convex with a concave region where it joins the alar process. The curve
continues on to the thicker anterior part of the process. Posteriorly the alar process
overlapped the pterygoid. This sutural surface is bordered laterally by a thickened
edge (Text-fig. 6A). The anterior end was probably sutured to the vomer. How-
ever, there is no definite sutural surface on the anterior part of the palatine which,
like the posterior part of the vomer, is damaged and incomplete.
Vomer (V) . The tapering head of this median bone is triangular in cross-section and
fits between the maxillae (Text-fig. 6A) . Ventrally the head sutured to the floor of
the premaxillae and the posterior limit of this suture is marked by a step (Text-fig.
6A). Slightly behind the head there is a dorsal groove that was for the median
cartilaginous septum. The groove becomes deeper as it passes posteriorly so that
the rest of the vomer consists of two thin sheets separated dorsally and curving out
laterally (Text-figs. 5C, 6A). Laterally there is a longitudinal ledge (Text-fig. 46),
the dorsal surface of which is convex dorso-ventrally while the ventral surface is
concave. This ledge was probably for the anterior part of the palatine. Ventral to
this ridge in RiQ4 there is a foramen, the ventral margin of which has been lost in
R2477 (Text-fig. 4B).
The lower jaw consists of seven bones and the two rami are linked anteriorly
by the median predentary. Only one predentary (PD) is known (Text-fig, n) and
this was preserved next to the dentary (see Nopcsa 1905, fig. 3). The dorsal surface
ISLE OF WIGHT, ENGLAND 39
(Text-fig. nD) is gently concave transversely while postero-medially the surface is
convex antero-posteriorly. The dorsal edge is sharp. The sides are gently convex
with a groove running diagonally back from the anterior end (Text-fig. nB). The
paired lateral processes overlap the adjacent lateral surface of the dentaries (Text-
figs. 3, zoA). Passing medially each process overlaps the dorsal edge of the dentary
to a progressively greater extent so that the anterior tip fits into a groove on the
posterior surface of the predentary (Text-fig. nC). The symphysial region is also
overlapped by the ventral process of the predentary ; the process is thin and trans-
versely curved (Text-figs. nD, E).
Dentary (D). In lateral view (Text-fig. loA) the spout-like anterior end of the den-
tary is longitudinally convex but the rest of the bone is concave, the surface sweeping
gently postero-laterally. The corresponding curves on the medial surface (Text-fig.
loC) are concave and then convex. The two rami diverge posteriorly, each becoming
progressively deeper and thicker, the additional thickness being lateral to the tooth
row (Text-fig. loB). The transverse curve of the lateral surface becomes more
convex posteriorly while, apart from the ventral Meckelian canal, all the medial
surface (Text-fig. loC) is gently convex. This canal ends just behind the symphysis
and is deeper posteriorly, with the dorsal part enclosed by an edge from the dentary.
The splenial covered most of this canal ; the canal carried the mandibular artery and
vein plus the palatine ramus of the trigeminal nerve as in modern lizards (Romer
1956). About half-way along the dentary the canal opens into the adductor fossa,
which greatly increases in depth (Text-fig. 12) and width posteriorly. Close to the
symphysis the ventral edge is sharp ; the rest is rounded. There are several foramina
along the lateral surface of the dentary which may have transmitted nerves and
nutrient blood vessels to the lips. The most anterior and largest of these foramina
probably represents the mental foramina through which a branch of the fifth nerve
emerged (Gilmore 1909).
Anteriorly the two dentaries meet at a median and somewhat obliquely inclining
contact surface (Text-figs. loB, C). The splenial and coronoid overlap the dentary
medially (Text-fig. loC). The part of the dentary overlapping the angular and
surangular (Text-fig. loC) is thin but the part touching the coronoid is thick with
strong sutural markings.
Splenial (SPL). This is thin and was applied to the inner surface of the mandibular
ramus (Text-fig. loC). It is gently convex longitudinally and more strongly so
transversely, especially the ventral part that wraps round the ventral edge of the
ramus and is visible in lateral view (Text-fig. loA). This ventral edge is thick and
rounded ; the other edges are thin and sharp.
Angular (A). This is thin and tapering (Text-fig. loA) and the ventral part is trans-
versely convex. Dorsally it overlaps the surangular (Text-fig. loA) while ventro-
medially it overlaps the prearticular and part of the articular and is itself overlapped
by the splenial (Text-fig. loC).
Surangular (SA). This is thin and in lateral view (Text-fig. loA) is transversely
convex ; longitudinally the dorsal part is gently convex, the ventral part gently
4o
THE WEALDEN HYPSILOPHODON
ISLE OF WIGHT, ENGLAND 41
concave. There are three foramina through the bone, two smaller ones posteriorly
and one large one anteriorly, which were probably for the cutaneous branches of the
inferior alveolar nerve as in modern lizards (Oelrich 1956). The most dorsal part
of the anterior edge fits into a groove in the coronoid. The dorsal edge is thick,
especially close to the coronoid. This edge also forms a well-developed boss just
in front of the articular. The part overlapping the articular is thick and roughly
oval in cross-section with a rounded dorsal edge.
Prearticular (PA). This is flat, tapers posteriorly and overlaps the dentary and is
itself overlapped by the splenial and the coronoid (Text-fig. loC). The ventral edge
is overlapped by the angular. The prearticular then widens out again. The
posterior part consists of two transversely convex curves separated by a thin slit
(Text-fig. loC) through which the chorda tympani branch of the seventh nerve
probably passed as in other reptiles (Romer 1956). More posteriorly the bone
becomes transversely convex and then flat and overlaps the articular.
Articular (ART). The articular is roughly triangular in lateral view with one apex
dorsal in position (Text-fig. loA). The rounded anterior edge is thin but the rest
of the bone is much thicker. The ventral edge forms a flat surface while the posterior
edge, which is concave in lateral view (Text-fig. loA), is gently convex transversely
and formed the articular surface for the quadrate. The articular is overlapped
laterally by the surangular, ventrally by the angular and medially by the prearticular.
ii) TEETH AND TOOTH REPLACEMENT
Dental formula. There are five teeth on each premaxilla (Text-figs. 2, 4). The
number of maxillary teeth is ten (Text-fig. 6A, left side) or eleven (Ri97, R2477,
Text-fig. 6A and R5862, Swinton 1936, fig. i). The predentary is toothless and the
number of teeth borne by the dentary is not certain as the dentaries of Ri97 and
R2477 are incomplete anteriorly. In R8366 the anterior part of the dentary is
preserved and this bears four smaller alveoli at the front. In R2470 the roots of
teeth are preserved in these four smaller alveoli. In Ri96 (Text-fig. 10) the complete
dentary is preserved but it is slightly damaged and some of the teeth are missing ;
the most anterior of the smaller teeth is preserved and, assuming that there were
three more, the original count would have been 14. In the large individual Ri92,
the anterior part of the jaw is missing but there are 13 teeth of which only the most
anterior is small. A complete dentary is needed to show the number of teeth but
there were certainly more than on the maxilla, not less as believed by Hulke (1882)
and Parks (1926).
Premaxillary teeth. The five premaxillary teeth are preserved in situ on the left side
of Ri97 (Text-fig. 2A). In the toothless premaxilla R83&7 the sockets for the teeth
are visible and these closely resemble those of the maxilla as figured by Swinton
(1936, fig. i). A loose tooth is figured by Hulke (1882, pi. 72, figs. 3-4) and one from
Ri96 in Text-fig. 13. The root is separated from the head by a slight constriction
and is circular in cross-section. The root is open with a large pulp cavity which
extends into the crown (Hulke 1882). The crown is slightly compressed laterally
THE WEALDEN HYPSILOPHODON
E
E
o
FIG. 13. Hypsilophodon foxii. Predentary tooth RIQ6, x 4. a, lateral view ; b, anterior
view ; c, medial view. Arrow in text-figs. 13 to 1 6 points anteriorly or laterally depending
on the view.
with the outer surface of its cross-section less convex than the inner. The pointed
crown has sharp edges anteriorly and posteriorly which bear a series of fine serrations.
On the medial surface (Text-fig. I3c) there is a slight depression running diagonally
towards the tip on each side. Both surfaces are smooth - that of the root is rather
matt while that of the crown is very shiny and obviously thickly enamelled on both
sides (visible in section of R2472) . There are several minute striae on both sides of
the crown.
Maxillary and dentary teeth. These are preserved in skulls (Text-figs. 2, 6 A, 12) and
loose teeth were figured by Hulke (1873, pi. 18, figs. 4-6 ; 1882, pi. 72, figs. 5-9),
Swinton (1936, figs. 2-3) and in Text-figs. 14-16. The crowns of both types are
laterally compressed and wider than the root, which is cylindrical and tapering. One
side of the crown (the lateral side of the maxillary teeth and the medial side of the
dentary teeth) is covered with a thick layer of enamel and bears several longitudinal
ridges. On the upper teeth these ridges are all weak but on the lower teeth the central
ridge is extremely well developed. The other side of the tooth is smooth and shiny.
Ground sections show that there is a thin layer of enamel on unworn teeth (R84I9),
as Swinton (in Sternberg 1940) suggested, and in worn teeth (R2472) as well. In
the section of the unworn dentary tooth R84I9, in which the width of the crown is
5-5 mm, the medial enamel layer at o-i mm is about five times as thick as the lateral
layer. The thickly enamelled edge of the tooth was more resistant to wear and
formed a sharp edge to the worn surface of the tooth. The obliquely inclined
occlusal surface of some teeth is gently concave transversely and flat longitudinally.
Maxillary teeth in longitudinal section curve slightly medially (Text-fig. I4a). The
root is about twice as long as the unworn crown. A depression runs along the
anterior edge of about half of the root and continues a little way on to the crown
(Text-fig. I4A). The crown of each tooth slightly overlaps the tooth behind and fits
against this anterior depression. The boundary between the root and the crown is
formed by a slight cingulum. The crown is laterally compressed and, apart from the
ISLE OF WIGHT, ENGLAND
43
£
E
o
FIG. 14. Hypsilophodon foxii. Unworn maxillary tooth R8367, x 4. a, anterior view ;
b, lateral view ; c, unworn dentary tooth right side R836y, x 4, lateral view. Abbrevia-
tion : a, depression for the more anterior tooth.
slight longitudinal ridges, the outer thickly enamelled surface is flat ; the inner
surface is very slightly concave longitudinally, gently convex transversely. In an
unworn tooth the rounded apex is somewhat posterior to the centre of the crown.
The number and degree of development of the longitudinal ridges on the enamelled
lateral surface of the crown varies. There are usually three ridges which reach the
cingulum : an obliquely inclined ridge on the antero-dorsal edge of the crown,
another from the apex and a third close to the posterior edge of the crown. Extra
ridges may be developed on the wider anterior part between the oblique ridge and
the apex ridge. Up to three ridges may be present and may or may not reach the
cingulum. The anterior edge bears several small crenellations and there are a few
others between the apex and the posterior ridge. There are numerous faint longi-
tudinal ridges on the thinly enamelled medial side.
Dentary teeth (Text-figs. 15, 16) are orientated in the reverse way to those of the
maxilla. The ridged and thickly enamelled surface is medial, instead of lateral ;
the tooth curves laterally, instead of medially ; more of the crown is posterior,
instead of anterior to the apex and the oblique ridge is posterior instead of anterior.
The cingula of dentary teeth are more strongly developed, the apices are more pointed
and more central on the crowns. However, the striking difference is the prominent
development of the apical ridges of the dentary teeth. The other longitudinal
ridges are faint, resembling those of the maxillary teeth, but the apex ridge is very
large and forms a well-developed 'spike' as the crown is worn. In large teeth there
may be several fine longitudinal ridges on the lower half of the apex ridge. The
degree of development of the anterior ridge varies and it may be practically absent.
The number and lengths of the ridges developed between the apex and the posterior
oblique ridge vary : there may be an anterior long one plus a short one, or just an
anterior short one. The anterior and posterior edges both have numerous fine
crenellations.
44
THE WEALDEN HYPSI LOPHODON
FIG. 15. Hypsilophodon foxii. Worn dentary tooth, right side, R836y, x 4. a, medial
view ; b, posterior view ; c, lateral view ; d, anterior view. Abbreviations : a, depres-
sion for the more anterior tooth ; os, occlusal surface.
Special foramina and replacement teeth. On the medial surface of the maxilla above
the tooth row there is a series of foramina connected by a shallow groove (Text-fig.
5A). Each foramen corresponds to a tooth position and is situated directly above it.
The edges of the foramina are straight ventrally and gently concave dorsally. The
bone surface between the foramina and the tooth row is pitted. The foramina open
into the alveoli of the functional teeth. A comparable series is present on the
dentary (Text-fig. loC). In certain cases (maxilla of R$862 and R6$J2, dentary of
R2477 and R8366) a replacement tooth is visible through a foramen.
Edmund (1957) discussed the function of the special foramina in ceratopsians and
hadrosaurs. He concluded that these foramina were for the admission of parts of
the dental lamina or for the admission of young replacement teeth produced by the
lamina. Edmund (1957 : 13) noted that the foramina ' are not seen in primitive
forms, are seen in some of the more advanced forms, and are best developed in forms
with very high alveolar walls. This definitely points to their function as orifices for
the admission of dental germinal material.' While not disputing Edmund's con-
clusion concerning the function of these foramina, it should be noted that they are
well developed in Hypsilophodon (Text-figs. 5 A, loC), Dysalotosaurus, Camptosaurus
and Iguanodon (see Galton in press). Their absence in other lower ornithopods is
probably more apparent than real and reflects the state of preservation of the material.
These foramina represent a preadaptation for the development of a dental battery
consisting of vertical tooth series, because high alveolar walls can be developed
(Galton in press). This potential was realized independently in two lines of orni-
thischians, the hadrosaurs and the ceratopsians.
In Hypsilophodon a small replacement tooth is preserved in the alveolus where it
is closely applied to the medial surface of the functional tooth. At a later stage in
ISLE OF WIGHT, ENGLAND
45
E
E
o
FIG. 16. Hypsilophodon foxii. Well-worn dentary tooth, right side, R8367, x 4. a,
lateral view ; b, posterior view ; c, medial view. Abbreviations : a, depression for
the more anterior tooth ; de, dentine ; e, enamel ; os, occlusal surface.
its development the replacement tooth is more lateral in position because it is under-
neath the functional tooth. When this situation is visible, as in the dentary of
specimens Rig2, Rig6 (Text-fig. zoC) and R2477 (Text-fig. I2B), the root of the
functional tooth is much shorter than the original length of the crown. Resorption
of the root must therefore have occurred because in an unworn tooth the root is
about twice as long as the crown. A functional tooth in this condition was readily
shed so that the replacement tooth could continue growing upwards into its position.
In the case of the premaxilla the bone medial to the tooth row is obliquely inclined
(Text-fig. 56) rather than vertical as in the maxilla and dentary. However, the
situation is similar because the replacement tooth is close to the medial surface of the
functional tooth and lateral, but also ventral, to the foramina. There are five pre-
maxillae with teeth - 24 preserved in all - but only one case ^5830) preserves a
non-functional replacement tooth in the alveolus.
Sequence of tooth replacement. In a study of tooth replacement in reptiles Edmund
(1960) found that all the teeth with 'odd' numbers in a numbered tooth series are
replaced in sequence, followed by all the 'evens'. The pattern of waves of tooth
replacement in most cases pass anteriorly so that the teeth of each 'odd' or 'even'
series erupt progressively from back to front. In Hypsilophodon this general pattern
is discernible in the tooth rows of the premaxilla, maxilla and dentary. It is
especially clear in the right maxilla of R2477 in which ten teeth (Text-fig. 6 A) are
well preserved. If the youngest tooth and the most worn tooth are designated as
stages i and 6 respectively, then the stage of eruption of the remaining teeth can be
assessed on this scale (Table IV). Apart from the first tooth, the teeth in the right
maxilla clearly show that replacement is alternate, with replacement waves passing
anteriorly. Both ' odd ' and ' even ' tooth series show two replacement waves - the
junction of those of the 'odd' series is between tooth 3 and 5 and that of the 'even'
teeth between 8 and 10. The first tooth is out of sequence as is also the case on the
left maxilla (likewise the last tooth of the dentary) ; these teeth, however, are small
46 THE WEALDEN HYPSILOPHODON
and have no wear surfaces. The replacement sequence of the premaxillary teeth of
R2477 is not apparent. In specimen R8367, however, where the functional teeth have
been lost, there are replacement teeth in the medial part of sockets i, 3 and 5 but
not in 2 and 4, so here too the replacement appears to have been alternate.
TABLE IV
Stages of eruption of teeth at various positions along the jaw in R2477
Tooth position i 2 3 4 5 6 7 8 9 10111213
a) Left maxilla 6 x x 6 5 2 5-5 5 2 5-5 4-5 - -
b) Right maxilla 13-554253652-5-
c) Right dentary x x x x 5-5 2-5 6 3 2 5 2 6 i
iii) ACCESSORY ELEMENTS
Hyoid apparatus. In specimens Rig2 and Rig6 there are remains of a slender
element preserved medial to the mandibular ramus. In Rig6 this element is gently
curved along its length and transversely flattened - it is about 2-5-3-0 mm wide and
more than 40 mm long, being broken at both ends. In RiQ7 (Text-fig. 2C) the edges
are more rounded while in Rig2 the small pieces that are preserved on both sides are
definitely rod-like. These are regarded as the first ceratobranchial because this is the
dominant and most highly ossified element of the hyoid apparatus in modern reptiles
(see Ostrom 1961).
Sclerotic ring. Hulke (1873 : 523), when referring to an individual in situ in marl
(remains as specimens R2466-76), noted that in the orbit there were 'several small
osseous scales which [he] judged to be vestiges of a sclerotic ring'. Subsequently
(1874, 1882) he figured the 'thin bony scales' of another specimen, R2477. Nopcsa
(1905) reinterpreted this specimen correctly and showed that the sclerotic plates
were the wear surfaces of the dentary teeth. He therefore concluded that there was
no sclerotic ring in Hypsilophodon. Hulke's original observation (1873) on R2466-
76, however, has been confirmed by the further preparation of the skull material.
Further, a nearly complete sclerotic ring is preserved in one orbit of R2477 (Plate i,
fig. 3) with several plates in the other orbit. Plates are also preserved in Rig2 and
Ri97 (Text-fig. 26).
The presence of a sclerotic ring in Hypsilophodon is not surprising because it has
been found in several dinosaurs (Edinger 1929, Ostrom 1961) and in Parksosaurus
(Galton, in press, fig. i). Where it can be determined, the sclerotic pattern of
dinosaurs conforms to pattern A of Lemmrich (1931), with two positive plates and
two negative plates. The ring is divided into four quadrants which are not necessarily
equal in size. The positive plates are dorsal and ventral in position and overlap
another plate at both ends. The negative plates are anterior and posterior in posi-
tion and are overlapped by another plate at both ends. The sclerotic ring of Cory-
thosaurus (see Ostrom 1961) and Lambeosaurus (see Russell 1940) consists of 14 plates
while in Anatosaurus there are 13 plates (see Edinger 1929).
The sclerotic ring of Hypsilophodon consists of 15 plates (Text-fig. 17) . The antero-
dorsal quadrant has been eliminated because the dorsal positive plate overlaps the
ISLE OF WIGHT, ENGLAND 47
3cm
FIG. 17. Hypsilophodon foxii. Sclerotic ring R2477, x i. a, lateral view ; b, ventral
view ; c, reconstruction.
anterior negative plate with no intervening plates. Although not previously reported
in dinosaurs this condition is known in several birds including all the members of the
family Phasionidae (partridges and pheasants ; Lemmrich 1931). The antero-
ventral quadrant has four intervening plates ; the postero-ventral quadrant has three
and the postero-dorsal quadrate has four.
The individual plates of the ring are gently convex longitudinally. In cross-
section the outer part is gently convex and the middle and inner parts are gently
concave. In RiQ7 (Text-fig. 2B) there is an isolated plate which is sub-rectangular
in outline with rounded edges ; this appears to be a positive or a negative plate.
The long edges of the individual plates in R2477 are damaged but the overlapping
part of each plate in the postero-dorsal quadrant clearly tapers to a point. This is
not shown by the other plates but a comparable difference is shown in the ring of
Sphenodon (Edinger 1929, fig. 23).
The length of the longest plate as preserved in R2477 has been used as the length
of the individual plates in the reconstruction. An overlap of about a half has been
assumed because this appears to be the amount of overlap between adjacent plates
in birds and reptiles (see Edinger 1929, Lemmrich 1931). The sclerotic ring is shown
overlapped by the supraorbital, but this may not be correct. As reconstructed the
diameter of the ring may be too large if some of the plates were smaller than the one
measured. In addition the degree of overlap may have been greater than half ; it
certainly is as preserved but this may be a post-mortem effect. The overlap would
also be reduced if, as was probably the case, the sclerotic ring were placed more
ventrally in the orbit than in the reconstruction.
Stapes. Unfortunately no trace of a stapes was found in the prepared skulls.
However, it is reasonable to assume that it was a rod-shaped element which, as in
hadrosaurs (Ostrom 1961), ran from the fenestra ovalis to a tympanum supported
between the quadrate and the paroccipital process.
THE WEALDEN H YPSILOPH ODON
B
OD.P I.C.1 d
AXIS
I.C.1
oc.c. — felij — od. p,
/ /
RA. pr.z. N.A. po.z.
n.a.
5cm
D
PA. N.A.
RA. N.A. OD.P
,-1'AXIS
AXIS
I.C.1
b) The vertebral column and ribs
The vertebral column can be assembled from specimens Rig6 and
complete presacral series consists of 24 vertebrae - 9 cervicals and 15 dorsals,
are 6 sacral and about 45 to 50 caudal vertebrae.
The
There
i) PROATLAS, ATLAS AND AXIS
Proatlas. That of R2477 is presumed to be the left but this, together with the
orientation shown in Text-fig. i8G, is only tentative. The proatlas of Rig6 is only
two-thirds the size of that of R2477 although the atlas and axis are slightly larger.
Atlas. This consists of an intercentrum, an odontoid process and two neural
arches. The intercentrum (Text-fig. 18) is a subcrescentic bone which anteriorly
has a large shallow depression for the occipital condyle (oc.c. Text-figs. i8B, H).
This depression is obliquely inclined with a sharp edge ventrally. More laterally
ISLE OF WIGHT, ENGLAND
49
ribl
I.C.I I.C.2 AXIS
5 cm
a
b
c
d
H
AXIS
od.p. ribl
I.C.1
ic2
FIG. 1 8. Hypsilophodon foxii. Proatlas, atlas and axis R2477, x i. A, dorsal view,
right neural arch removed ; B, atlas intercentrum, dorsal view ; C, lateral view with ribs
(rib 2 from Ri96) ; D, proatlas with atlas in medial view, axis in lateral view ; E, ventral
view ; F, odontoid process of axis in ventral view ; G. proatlas, view a = C, b = A,
c = D, d = E ; H, anterior view ; I, axis in anterior view ; J, odontoid process and
intercentrum of axis in posterior view. Abbreviations : 1C. i, intercentrum of atlas ;
1C. 2, intercentrum of axis ; OD.P., odontoid process of axis ; P.A., proatlas ; N.A.,
neural arch of atlas ; RIB i and 2, ribs of atlas and axis ; ax., surface for axis ; d,
diapophysis ; i.e., surface for intercentrum ; n.a., surface for neural arch of atlas ; n.a.a.,
surface for neural arch of axis ; oc.c., surface for occipital condyle ; od.p., surface for
odontoid process ; po.z., postzygapophysis ; pr.z., prezygapophysis ; rib 1., surface for
rib of atlas.
there are two surfaces, facing antero-dorsally and laterally, for the neural arches
(n.a. Text-figs. i8B, C, D). The central part of the dorsal surface is sunken with an
irregular though symmetrical outline (Text-fig. i8B). Ventrally (Text-fig. i8E)
the surface is concave antero-posteriorly, forming a distinct edge with the anterior
and posterior articular surfaces. Posteriorly, this surface medial to the rib facet is
concave transversely but the remainder of the surface is convex. This ventral
surface is covered with well-developed insertion markings. On the left side the
5o THE WEALDEN HYPSILOPHODON
anterior corner has a very irregular appearance (see Text-fig. i8E) which is not due
to breakage and must be an individual variation.
The dorsal surface of the odontoid process is transversely concave next to the axis
but becomes planar anteriorly (Text-fig. i8J). The ventral surface of the wedge-
shaped odontoid is transversely convex. The anterior crescentic area is flat apart
from a slight median depression (oc.c. Text-fig. i8H) with which the occipital con-
dyle articulated. The base is gently concave and the intercentrum articulated with
this surface (i.e. i Text-fig. i8I). Between these two surfaces and forming an obtuse
edge with each there is a concave area which, after a slight constriction, passes on to
the lateral surface to form a shallow depression (Text-fig. i8D). There is a sharp
edge antero-dorsally but more posteriorly the surface is indented slightly with a
gentle convex curve (Text-figs. i8A, D).
The neural arches (or neurocentra) are rather irregularly shaped bones which did
not meet each other dorsally. Ventrally there are two articular surfaces (Text-fig.
i8D) ; the larger posterior surface across the thicker part of the bone is for the inter-
centrum, the other faces slightly medially and contributes to the articulation for
the occipital condyle (oc.c. Text-fig. i8H). Above these facets the outer surface is
convex (Text-fig. i8C) and the inner slightly concave (Text-fig. i8D). On the outer
surface where the shaft is constricted there is a well-defined bump. Anteriorly the
region of the prezygapophysis forms a thin, curved sheet with two lobes (Text-fig.
i8A). The postzygapophyseal process is slender and directed postero-dorsally and
laterally (Text-figs. i8A, H). Medial to this the dorsal surface is concave. The
ventro-medial surface is concave apart from the flat postzygapophysis, facing ventro-
medially.
The atlantal rib (Text-fig. i8A) is long, laterally flattened and oval in cross-
section. The head, which articulated with the intercentrum, is slightly expanded
with an obliquely inclined concave surface. In Rig6 there is another single-headed
rib next to the axis but it is slenderer than the atlantal rib of R2477 which is a smaller
animal. It has also, close to its head, a small ventral plate which is presumably the
remains of the capitulum (Text-fig. i8C) ; it is probably the axial rib because the
rib of the third cervical vertebra was in position (Text-fig. 19).
Axis. The centrum is plano-concave with a shallow posterior depression. An-
teriorly there is an oval intercentrum (Text-fig. i8E), triangular in sagittal section,
with a sharp anterior edge. The neural arch has a well-developed and laterally
compressed neural spine (Text-fig. i8A) which posteriorly is laterally expanded to
form a frill-like plate (Text-figs. i8H, 2oB). The ventral part of this plate is thicker
and bears postzygapophyses which face ventro-laterally and slightly posteriorly.
Anteriorly the neural spine is slightly thickened to form a projecting knob (Text-fig.
2oB). The prezygapophyses are transversely convex and the postzygapophyses of
the atlas articulated round their lateral surface. The ventral edge of the prezyga-
pophysis continues on to the neural arch as a ridge below which the surface of the
neural arch is concave (Text-fig. i8D). This concave area is continuous with the
depression on the side of the odontoid process. The diapophysis (d. Text-fig. i8D)
is small and is traversed by the rather indistinct suture between the neural arch and
centrum. There does not appear to be a corresponding parapophysis on the
ISLE OF WIGHT, ENGLAND 51
centrum but this region is slightly damaged. However, it was probably absent
because the rib of the axis appears to have been single-headed.
ii) CERVICAL VERTEBRAE 3 TO Q
The centra of cervical vertebrae 3 to 7 are opisthocoelous while those of 8 and 9 are
amphicoelous. The centrum of the third cervical vertebra is laterally compressed ;
anteriorly there is a sharp ventral edge which widens out posteriorly where it is
covered with well-developed surface markings. The remainder of the centra are
also laterally compressed but ventrally the lateral surface curves outwards again to
form a thickened keel (Text-figs. 19, 2oA). The rounded ventral surface of this
keel is covered with strongly developed and irregular surface markings.
The neuro-central suture bisects the parapophysis and is clearly visible in all
cervicals (Text-fig. 19). The parapophyses of cervical vertebrae 8 and 9 are the
largest. The diapophysis shows a progressive increase in robustness and length. In
the fifth cervical it runs into the base of the prezygapophysis, in cervical vertebrae
6 to 9 the diapophysis is progressively more antero-dorsal in position on the side of
the prezygapophysis. The angle which the diapophysis makes with the vertical
in the transverse plane varies from 140 degrees in the third vertebra to 155 degrees
in the fifth and then to 80 degrees in the ninth. The postzygapophysis of the third
vertebra is quite slender with a well-developed dorsal ridge but distally it is flatter
and broader. The remaining postzygapophyses are wider and thicker so that the
dorsal ridge becomes progressively less conspicuous. Distally the postzygapophyses
are broader and flatter but the separation of this region is less well marked. On
this distal part in cervical vertebrae 6 and 7 there are well developed and irregular
surface markings.
In cervical vertebrae 3 and 4 the neural spine was probably only a slight ridge ; in
5 and 7 it is small and thick with a triangular lateral outline while in 8 and 9 it is
much larger, forming a thin triangular sheet. In cervical vertebrae 3 and 4 the pre-
and postzygapophyses form a continuous curve with the neural arch (Text-fig. 2oB) .
In the fifth there is a distinct excavation of the wall of the neural arch and the line
of the postzygapophysis continues antero-medially to the end of the neural spine.
In cervical vertebrae 6, 7 and 9 this lateral space between the pre- and postzygapo-
physes becomes slightly deeper anteriorly and slightly wider. However, in cervical
8 this space forms a narrow cleft as the body of the neural arch is considerably
enlarged. On the flat area so formed are well-developed insertion markings which are
adjacent to those on the postzygapophyses of the preceding vertebra.
The third rib, like those of the remaining cervicals, is double-headed. The
tuberculum is longer and wider than the capitulum. This rib lacks the anteriorly
directed spine present on the fourth rib (Text-fig. 19). The ribs of cervicals 4 to 9
show a number of progressive trends as illustrated (Text-figs. 19, 20). The capitulum
becomes longer, the anteriorly directed spine is reduced and the ribs become longer
and wider so that they are more sheet-like. In the seventh to ninth ribs the lateral
surface is convex, the medial surface concave, the anterior edge thick and rounded
and the posterior part thin and sharp-edged. In the eighth and ninth ribs there is a
non-articular extension of the capitulum on its medial side.
THE WEALDEN HYPSILOPHODON
ISLE OF WIGHT, ENGLAND
53
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THE WEALDEN H YPSILOPHODON
5 cm
FIG. 21. Hypsilophodon foxii. Dorsal vertebrae i to 8 of RIQ6, x i. A, dorsal view
B, lateral view ; C, ventral view. Abbreviations : d, diapophysis ; p, parapophysis.
ISLE OF WIGHT, ENGLAND
55
A
5cm
FIG. 22. Hypsilophodon foxii. Dorsal vertebrae 9 to 15 of Rig6 (supplementary details
from Ra477a), x i. Views and abbreviations as in Text-fig. 21.
56 THE WEALDEN HYPSILOPHODON
iii) DORSAL VERTEBRAE (Text-figS. 21, 22)
All the centra are amphicoelous. The posterior face of the last dorsal vertebra has
two lateral concave areas separated by a dorso-medial ridge. The length of the
centrum increases slightly with each successive vertebra. In the first dorsal the
middle part of the centrum is laterally compressed so that a thin ventral edge is
formed (Text-fig. 2iC). The degree of compression decreases posteriorly, so that
this ventral part becomes thicker and more rounded. The thicker anterior and
posterior regions of the centra are covered with muscle insertion markings which are
especially strong ventrally.
The diapophysis remains at about the same height on the neural arch throughout
the series (Text-figs. 2oB, 2iB). The level of the parapophysis drops quite sharply
from dorsals i to 4 but behind this there is only a very slight drop. The diapophysis
and parapophysis become progressively closer together and are united in the last
two dorsal vertebrae. In the first dorsal the prezygapophyses are large and wide
apart but in the next five vertebrae they become progressively smaller and closer
together (Text-fig. 20 A). Posteriorly the prezygapophyses become slightly longer
and the level varies as shown in Text-fig. 2iB. The articular surfaces of all the
prezygapophyses make an angle of about 45 degrees with the horizontal.
The angle between the transverse process and the vertical varies from 60 degrees
in the first dorsal to 70 degrees in dorsal 4 and 85 degrees in dorsal 8, the processes
being more or less horizontal in the remainder. The bases of the transverse processes
of the first five dorsal vertebrae become more ventral (Text-fig. 2oB) and posterior
(Text-fig. 2oC) in position. The thin overhanging part at the base of the transverse
process is reduced, passing posteriorly, so that more of the diapophysis becomes visible
in dorsal view (Text-fig. 2oA) . In the sixth dorsal the dorsal edges of the diapophysis
and the transverse process form a continuous curve. Posteriorly at its base the
transverse process forms a flattened sheet which continues as the postzygapophysis.
This sheet is small in the first dorsal but considerably larger in the second ; it is then
progressively reduced and is absent in the fourteenth and fifteenth dorsals. The first
neural spine is thin, the fifth is thicker and larger (Text-fig. 2oA, B) while the last
seven dorsals have a well-developed thickening dorsally so that a thick edge is formed
(Text-fig. 2iB).
All except the last one or two dorsal ribs are double-headed. Anteriorly the
thoracic ribs are curved, especially near their upper ends, with a superficially flat-
tened and broad distal part. Posterior to the seventh dorsal vertebra the ribs become
progressively shorter, straighter and the lateral expansion is lost. The capitulum is
borne on the proximal end of the rib while the tuberculum is on a more dorso-
laterally placed step and faces dorso-medially. On the anterior ribs the tuberculum
is widely separated from the capitulum but more posteriorly the two heads are pro-
gressively closer together ; thus they are scarcely distinguishable on dorsal rib 14
while rib 15 is single-headed. These last two ribs are fused with the end of the
transverse process.
The sternal segments of the dorsal ribs are always present but are not always
ossified. In RiQ6 the sternal segments of the first three dorsal ribs and part of the
fourth (Text-fig. 37E) are preserved on the left side together with parts of the first
ISLE OF WIGHT, ENGLAND 57
three of the right side (Text-fig. 376). The first three segments contact the thick and
roughened dorso-lateral edge of the sternum while the fourth contacts the distal part
of the third (Text-fig. 37E). Distally the first three segments become dorso-ventrally
flattened and thicker. In Parksosaurus the first six dorsal ribs have sternal segments
(Parks 1926) and this may have been the case in Hypsilophodon.
iv) SACRAL VERTEBRAE
There are two distinct types of sacrum found in Hypsilophodon ; the significance of
this dimorphism will be discussed below (p. 122).
The sacrum of Rig6 (Text-fig. 23) consists of six coossified centra. But the ribs
of the first vertebra are borne on the transverse processes and do not contact the
ilium (Text-figs. 23, 256) ; there are only five pairs of sacral ribs, which belong to
vertebrae 2-6. This is the pentapleural condition. Therefore, strictly speaking,
the ' first sacral' vertebra is a dorsal ; Rig6 has 16 dorsal vertebrae and 5 true sacrals.
Functionally, however, this last dorsal vertebra is an integral part of the sacrum
because the expanded posterior part of its massive centrum has an extensive sutural
contact with the first true sacral ribs (i.e. the ribs of the second vertebra, Text-figs.
23, 25E).
The sacra of Parksosaurus, Thescelosaurus and Dysalotosaurus are very similar to
this. In his description Parks (1926) - followed by Sternberg (1940) and Janensch
(1955) - numbered the massive dorso-sacral vertebra as Si and the other five ver-
tebrae as S2-S6 ; yet, oddly enough, the five pairs of sacral ribs borne by those five
vertebrae were numbered 1-5. Thus the second vertebra bears the first rib, the
third vertebra the second rib and so on down the series. Confusing though this may
seem, for the sake of consistency the same system of numbering will be applied to the
pentapleural sacrum of Hypsilophodon.
By contrast, in Ri93 and Ri95 the first vertebra (Text-figs. 24, 256, 27) is a true
sacral because its ribs suture with the centrum and neural arch and contact the
pubic peduncles of the ilia ; thus the sacrum in these individuals has 6 pairs of
sacral ribs. This is the hexapleural condition, with only 15 dorsal vertebrae but
with 6 sacrals. Because the ribs of sacral vertebrae 2-6 (numbered 1-5) are ob-
viously homologous to the 5 true sacral ribs of Ri96 and to those of other lower
ornithopods, Parks' system of numbering will be applied also to the hexapleural
sacrum of Hypsilophodon, with the second vertebra bearing the first rib and so on.
The problem then arises : how should the rib borne by the first sacral vertebra be
numbered in hexapleural individuals? The solution adopted, is to call it the ' new
sacral rib ' (Text-figs. 24, 256, 27 ; see Section vi). Though this too may be con-
fusing, it seems likely that worse confusion would result from a complete renumbering.
In Rig6 the anterior end of the first centrum is transversely expanded (Text-fig.
23C) and its face is markedly concave (Text-fig. 250). The slightly expanded pos-
terior surface of centrum 6 is very gently concave (Text-fig. 26D) . Each zygapophy-
sis makes about a right angle with the other but they are closer together posteriorly.
The postzygapophyses of sacrals i to 5 fit into a square space formed by the anterior
edge of the neural arch and the prezygapophyses of the next vertebra. In sacral i the
THE WEALDEN HYPSILOPHODON
B
6cm
FIG. 23. Hypsilophodonfoxii. Sacrum of Rig6 - pentapleural type, x i. A, dorsal view ;
B, lateral view ; C, ventral view. Abbreviations : r, rib of first sacral vertebra (dorso-
sacral) ; sa, sacral vertebra ; sa r, sacral rib.
ISLE OF WIGHT, ENGLAND
dor.15 sa.1
B
6cm
1 f
1 1
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/ til
, i i
sa.6
FIG. 24. Hypsilophodon foxii. Last dorsal vertebra and sacrum of Ri93 - hexapleural
type, x f. A, dorsal view, B, lateral view ; C, ventral view. Abbreviations : dor,
dorsal vertebra ; sa, sacral vertebra ; sa r, sacral rib ; sa r N, new sacral rib.
60 THE WEALDEN HYPSILOPHODON
transverse process is large and bears a free rib on its distal end. In the remaining
sacral vertebrae the transverse process is sutured ventrally and also (except in sacral
2) laterally to a sacral rib. The angle between the distal part of the transverse
process and the vertical varies, being 70 degrees in sacral i, 90 degrees in sacral 4
and 100 degrees in sacral 6. In sacral vertebrae i and 6 the sides of the neural arch
are excavated so that the anterior end of the base of the neural spine is thin. Pos-
teriorly there is a slight increase in thickness from sacral i to 3, then a decrease to
sacral 6. The lower half of each neural spine is thin anteriorly and posteriorly so
that the edges of adjacent spines touch. The anterior thin sheet is especially large
in sacrals 5 and 6 while the posterior thin sheet, which is developed between and
above the postzygapophyses, is largest in sacral 5 but absent in sacral 6.
V) SACRAL RIBS
The central sutures are not clearly visible in Rig6 (Text-fig. 23) but can be seen in
the four sacral vertebrae of Ri95, in which the different parts have been dissociated
(Text-figs. 256, E, F, 26A, 27 ; for sac. r. N see Section vi), and in RiQ3 (Text-figs. 24,
26B, C). Each sacral rib projects not from the middle of the centrum, but more
anteriorly, so that its anterior edge is borne by the centrum of the preceding vertebra.
The base of each rib contacts the lower surface of the transverse process and it is
sunk into the side of the neural arch. The flat ventral surface of the first sacral rib
is level with the ventral surface of the centrum (Text-fig. 236). Proximally the
bases of the remaining sacral ribs are high on the centrum, with the second slightly
higher than the others.
In Rig6 the dorsal parts of the sacral ribs vary (Text-figs. 23 A, B). In the first
sacral rib the dorsal part is thin with a sharp dorsal edge. In the second and third
sacral ribs it is still thin, but its dorsal edge is thicker and is attached to the end of
the transverse process. In the fourth sacral rib all the dorsal part is thicker and
postero-dorsally inclined. There is a progressive dorso-ventral flattening of the
more distal part of sacral ribs 3, 4 and 5 (Text-fig. 236) so that the fifth rib (Text-fig.
26D) is practically horizontal and the thickened dorsal edge has merged with the
rest of the rib. On the dorsal surface of the ribs and transverse processes there are
well-developed markings across the line of suture. These are absent on the second
sacral vertebra, the transverse process of which does not contact a sacral rib at its
lateral end ; consequently the muscles concerned presumably attached to the end
of this process.
VI) THE HEXAPLEURAL TYPE OF SACRUM
In specimens of this type (Ri-93, Ri95, R2477a, R582g, R583O) the rib of the first
sacral vertebra is no longer a free dorsal rib, but has become a sacral rib ; this
vertebra is therefore a true sacral rather than a dorso-sacral vertebra. The rib is
no longer attached to the transverse process, but is borne ventrally and sunk into
the side of the centrum and neural arch (Text-figs. 24, 256, D, 27). The rib base is
enlarged antero-posteriorly and is partially borne by the centrum of the preceding
vertebra (Text-figs. 246, 256, D, 27!$). Thus, in comparison with the pentapleural
ISLE OF WIGHT, ENGLAND 61
type with five sacral ribs (Text-fig. 23 ; R2477b, R8422), there is an additional
sacral rib which is termed the ' new sacral rib ' (see above) . This rib has a constricted
shaft beyond which it is slightly expanded and meets an anterior projection from the
proximal end of the first sacral rib. The distal face of this new rib forms a smooth and
slightly concave surface (shown in Ri95, right rib).
The new position of the rib of the first sacral vertebra has resulted in a few dif-
ferences in the form of the vertebra when compared with that of the first sacral
(dorso-sacral) of the pentapleural type described above. The transverse process,
because it no longer bears the rib, is very thin dorso-ventrally. In anterior view
(Text-figs. 256, D) it tapers to a point and there is no distal facet. There are no
well-developed muscle scars on the distal part of the dorsal surface as the muscles
concerned inserted on the lateral end of the process. Anteriorly the sides of the
neural arch and the centrum are recessed for the new sacral rib.
The sacrum of R5829 differs somewhat from the other hexapleural sacra. The
new sacral rib is rather damaged but it was certainly sutured to the side of the first
sacral centrum and neural arch. Dorsally the right transverse process of the first
sacral vertebra bears well-developed muscle scars. These insertion markings are
found only when a rib is present and they run across the line of suture between the
rib and the transverse process. Because these markings are complete the proximal
part of the new sacral rib is still attached to the end of the transverse process (the
rest of the rib is lost). Consequently the new sacral rib in R582Q has the same con-
nections with its vertebra as do the other sacral ribs. The first sacral rib (i.e. the
rib of the second sacral vertebra) bears an anteriorly directed process that would
have met the new sacral rib. However, the dorsal edge of the first sacral rib is
thickened ; it is sutured to the end of the transverse process and there are muscle
striations running across the line of suture. This is in contrast to all other sacra,
pentapleural or hexapleural, in which this rib has a sharp dorsal edge and there is no
contact with the distal end of the transverse process.
Vii) OTHER VARIATIONS IN THE SACRUM
The degree of contact between the neural spines of the sacral vertebrae varies
(Text-figs. 236, 246, 276). In RiQ3 and Rig6 the part of the spine adjacent to the
contact edge consists of a thin sheet. In RiQ5 and R2477a the whole of the neural
spine is thick with well-developed sutural ridges along the contact edge (Text-fig.
25E). In addition there is a small sutural contact between the neural spine bases of
the fifteenth dorsal vertebra and the first sacral vertebra (Text-fig. 256). This
contact is also present in R582Q but there are no comparable sheets between the
zygapophyses of the other specimens. The degree of fusion of the neural spines is
an individual variation because it is not related to the size of the specimens (see list
below). The ankylosis of the neural arch and the centrum of the sacral vertebrae
appears to be an age variation. The length of the first three centra of the sacrum is
the best index of size available. The neural arch and centrum are separate (as are
the individual centra) in R5830 (38 mm), and Rig5 (51 mm) but they are all anky-
losed in R2477a (+ 50 mm), R2477b (54mm), Rig6 (55mm), R582Q (± 67 mm),
62
THE WEALDEN H YPSI LOPHODON
B
sa. r. N
sa. r. N
sa. r. 2
FIG. 25. Hypsilophodon foxii. Anterior view of vertebrae. Dorsal vertebra : A,
fifteenth of R 1 95, x i. Sacral vertebrae : B, first of RiQ5, xi; C, first of Rig6 (dorso-
sacral), x i ; D, first of RiQ3, x f ; E, second of Rigs, x i ; F, third of RiQ3, x f .
Abbreviations : r, rib of first sacral vertebra ; sa r, sacral rib ; sa r N, new sacral rib.
ISLE OF WIGHT, ENGLAND
B
sa. r. 4
r 3
sa. r. 5
FIG. 26. Hypsilophodon foxii. Anterior view of sacral vertebrae. A, fourth of Ri93,
x $ ; B, fifth of Ri93, x f ; C, sixth of Rigs, x £ ; D, posterior view of sixth of Rig6,
x i. Abbreviations : sa r, sacral rib.
R8422 (71 mm) and Ri93 (75 mm). The anterior face of the centrum of the first
sacral varies ; it is transversely concave in Rig6 (Text-figs. 236, 256), almost flat
in Ri-95 (Text-figs. 256, 276) while in RiQ3 (Text-figs. 246, 250) the medial part is
flat with deep dorso-lateral depressions in the region of the new sacral rib. The
ventral surface of the first two centra varies : the medial part of the first of Rig6
(Text-fig. 236) is rather flat while in RiQ3 (Text-fig. 246) and RiQ5 (Text-fig. 276)
it is transversely convex and longitudinally concave ; that of the second is trans-
versely concave in RiQ5 and Rig6 but convex in RiQ3.
Viii) CAUDAL VERTEBRAE AND CHEVRONS
In the small individual Rig6 the first 19 caudals are present while in the larger
individual Ri96a there are 29 from the posterior part of the tail. The first vertebra
without a transverse process is the eighteenth caudal of Rig6 and the ninth preserved
THE WEALDEN HYPSILOPHODON
FIG. 27. Hypsilophodon foxii. Dorsal vertebrae 14, 15 and sacral vertebrae i to 4 of
Ri95, xi. A, dorsal view ; B, lateral view ; C, ventral view. Abbreviations: dor,
dorsal vertebra ; sa, sacral vertebra ; sa r, sacral rib ; sa r N, new sacral rib.
ISLE OF WIGHT, ENGLAND 65
vertebra of Rig6a. This suggests that the first 9 tail vertebrae are missing in the
latter series, those present being caudals 10 to 38. The most posterior caudals
present are not greatly shortened. A comparison with the tail in Thescelosaurus
(see Gilmore 1915) indicates that 10 or so vertebrae are probably missing from the
distal end of the tail of the larger specimen.
The first caudal centrum is opisthocoelous but the remaining centra are amphi-
coelous. Throughout the series the centra become progressively lower and thinner.
Posterior to the eighteenth caudal the lateral and ventral surfaces become flatter
so that the ventral edge is square in section. In addition there is a square dorsal
outline above. All the transverse processes point slightly upwards at an angle of
about 10 degrees to 15 degrees to the horizontal. The distal part is postero-ventrally
directed only in the first caudal (Text-figs. 28A, C, 3oA, C). Some of the variation
in the horizontal plane (Text-figs. 29, 31) is due to distortion. The transverse pro-
cess of the seventeenth caudal is represented by a very slight bump with no trace at
all on the eighteenth.
In the first 12 caudal vertebrae the articular surfaces of the zygapophyses become
progressively smaller, more vertical and closer together but then remain constant in
the remaining caudals preserved. In lateral view (Text-fig. 28A) the prezygapophy-
ses become thinner but the length remains about the same. However, internally the
space at the base of the prezygapophyses is filled in with bone. By caudal 12 the
postzygapophyses have become round vertical plates close together on the edge of
the neural spine. They are embraced by the correspondingly small prezygapophyses.
The main body of the neural arch becomes progressively lower and thinner along
the series. The neural spine of the first caudal is slightly taller and narrower than
in the last sacral vertebra. The thin anterior part is less extensive but the part of
the spine dorsal to the postzygapophyses is thicker. The anterior thin part is
progressively reduced in the first six caudals so that the neural spine is slightly
shorter ventrally (Text-fig. 28A). Posterior to the ninth caudal the neural spines
become progressively lower but the ventral part becomes wider. The neural spines
seem to disappear at about the thirty-sixth caudal in Ri96a.
The first chevron is borne between the centra of the first two caudals and was
found in place in Ri96 (Text-fig. 28A). In Ri93 this region had already been pre-
pared but a chevron was originally present because these two centra have the same
facets (Text-fig. 3oA). Hulke (1882 : 1046) stated that the second caudal has 'a
single facet, the first chevron being articulated with the second and third caudal
vertebrae'. However, the condition of the second centrum cannot be determined
from his figure (Hulke 1882, pi. 74, fig. 9) and this specimen cannot be found. The
first chevron is a small nubbin of bone that is slightly flattened dorso-ventrally
(Text-fig. 28A). The ventral part is damaged and there may have been bone
enclosing the haemal artery. The second chevron appears to be flattened antero-
posteriorly while the third is circular in cross-section and tapers distally (Text-figs.
28A, B). In the fourth and successive chevrons the distal part becomes longitudin-
ally expanded and flat while the proximal part becomes narrower with the formation
of a short shaft region. In all the chevrons the articular surface for the preceding
centrum is slightly smaller than that for the posterior one.
66
THE WEALDEN H YPSI LOPHODON
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THE WEALDEN HYPSILOPHODON
ABC
FIG. 32. Hypsilophodon foxii. Caudal vertebrae of R5830, x i. A, about the twenty-
fourth ; B, about the twenty-eighth ; C, about the thirty-seventh ; a, lateral view,
b, ventral view ; c, dorsal view.
4cm
B
dor. 11
FIG. 33. Hypsilophodon foxii. Ossified tendons of Ri96, x i. A, dorsal vertebrae 6-10
in dorsal view ; B, dorsal vertebrae 11-15 in dorsal view ; C, sacrum in dorsal view ;
D, caudal vertebrae 13-18 in lateral view. Abbreviations : ch., chevron ; dor., dorsal
vertebra ; sa., sacral vertebra : t.p., transverse process.
ISLE OF WIGHT, ENGLAND 71
c) Ossified tendons
Anteriorly, fragments of ossified tendons remain on the fifth dorsal of Rig6 but
no tendons were found when the third dorsal was prepared. These vertebrae were
in natural articulation and the fourth dorsal vertebra probably marks the anterior
limit of the ossified tendons. Most of the tendons of the dorsal and sacral series of
Ri96 lie immediately above the neural arches. However, this may not be natural
because in Ri95 and R2477 the tendons occurred along the sides of the neural spines.
In Ri95 the individual tendons span at least five vertebrae, running horizontally and
close to one another ; they do not show the rhomboidal arrangement present in
Iguanodon (see Dollo 1887) and the hadrosaurs (Lull & Wright 1942, Colbert 1962).
The number of tendons on one side of a vertebra varies from six to nine but originally
there were probably many more.
4cm
'ch.13
72 THE WEALDEN H YPSILOPH ODON
Only a few tendons were found when the proximal part of the tail of Rig6 was
prepared and this probably reflects the original situation. The tendons on the chev-
rons of caudal vertebrae 14 to 17 are well preserved (Text-fig. 33D) and each consists
of a flat sheet of bone, with fine longitudinal striations, one end of which tapers to a
point while the other splays out into a series of fine rays. The complete series of
rays is not preserved for any single tendon but there were at least ten per tendon.
Each tendon is intervertebral in position and is about the same length as one of the
adjacent centra. The tendons are arranged in rows, the individual tendons of which
point in the same direction (Text-fig. 33D) while adjacent rows point in the opposite
direction.
The posterior third, at least, of the tail was ensheathed by a large number of ossified
tendons (Text-fig. 62). On one side of the twenty-seventh caudal of Ri96a there
are 28 tendons in a width of 23 mm. However, there are many more than this
because there are others below and, in addition, quite a few appear to have been
removed during preparation. The individual tendons can be followed for a length of
only two centra at the most but, because they are rather damaged, they may
originally have been considerably longer. The splaying of the end of the tendon
into many rays is visible in several places with both anteriorly and posteriorly
pointing tendons represented.
In the dorsal and sacral series of Rig6 (Text-figs. 33A-C) the splaying is visible
in a few places. However, all of these point anteriorly with a posterior splaying.
There are a few anterior ends that are different, being slightly flattened laterally with
a few strongly developed ridges and an uneven surface. Individual tendons are
much longer than those of the tail and for most of their length are circular in cross-
section, but they have the same fine longitudinal striations as the tendons of the
caudal series.
d) Appendicular skeleton
l) THE PECTORAL GIRDLE
Scapula. This is about the same length as the humerus, is twisted along its length
and, in addition, bowed (Text-fig. 346) so that it followed the outer contour of the
rib cage. The anterior end of the base of the scapula bears a triangular facet (cl.
Text-figs. 34A, 35A) with a rounded articular surface which was probably for the
clavicle. In ornithischians the clavicle itself is preserved in Protoceratops (see Brown
& Schlaikjer 1940) and psittacosaurs (Osborn 1924). The anterior edge of the
scapular blade is thin and rounded as is the posterior edge, apart from the dorsal
part which is sharp. The dorsal edge is thicker where it cuts across the body of the
blade and it is rather bumpy. This dorsal end-surface probably carried a cartila-
ginous suprascapula as described in Parksosaurus by Parks (1926). The lateral
surface of the scapula immediately behind the clavicular facet forms a well-developed
depression (Text-figs. 34A, 35A). This is continued diagonally upwards as a concave
surface running along the convex curve of the scapula to meet another diagonally
inclined depression from the glenoid region. Ventrally the central part forms a
ISLE OF WIGHT, ENGLAND
73
B
4cm
c.for.
FIG. 34. Hypsilophodon foxii. Scapula and coracoid Ri96, x i. A, lateral view ;
B, anterior view. Abbreviations : C, coracoid ; SC., scapula ; c. for., coracoid foramen ;
cl., facet for clavicle ; gl. cav., glenoid cavity.
rounded surface that projects beyond the coracoid (Text-fig. 34). The medial sur-
face (Text-figs. 346, 356) is slightly concave dorso-ventrally and convex antero-
posteriorly. The ventral part forms a broad convexity which is crossed by a groove
leading from the coracoid foramen (Text-fig. 356).
The scapulae show a certain number of individual variations. Posteriorly the
junction of the shaft and the blade forms a step in Rig6 (Text-fig. 34A) and Riga
which is practically absent in R582Q and R583O (Text-fig. 36A). The shaft is more
strongly twisted in Rig6 (Text-fig. 34) than it is in Rig2, R$82g and R5830 (Text-
fig. 36). The coracoid groove is deeper in Rig6 (Text-fig. 356) than it is in R582Q
74
THE WEALDEN HYPSI LOPHODON
FIG. 35. Hypsilophodon foxii. Scapula and coracoid Ri96, x i. A, ventro-lateral
view ; B, dorso-medial view. For abbreviations see Text-fig. 34.
or R5830. All these are random variations independent of size. The lateral edge
running from the facet for the clavicle is strongly developed in RIQ2, Rig6 (Text-fig.
34A) and R5829 but weakly so in R5830 (Text-fig. 36A). The sutural surface with
the coracoid has well-developed ridges in Rig6 which are absent in R583O. The
general curves of the scapula (and coracoid) of Rig6 (Text-figs. 34, 35) and R582Q
are more strongly developed than in R5830 (Text-fig. 36) ; all these differences are
probably due to the smaller size of R5830.
Coracoid. The coracoid is thin except for the dorsal part. The inner surface
(Text-figs. 346, 356) is concave dorso-ventrally and convex antero-posteriorly, with
a strongly developed depression on the antero-ventral part where the edge is very
thin (Text-fig. 356) . Dorsally, the inner surface has a large raised area in the middle.
The coracoid foramen (Text-fig. 356), which extends diagonally forwards and down-
wards through the bone (visible in R5830), is located in the posterior part of this area.
A well-marked groove (Text-fig. 356) extends dorsally from the coracoid foramen and
continues on to the scapula.
Sternum. The right sternal bone is longer than the left (Text-fig. 37), but this is
presumably an individual variation. The antero-medial part is thick with an
irregular sutural surface (Text-fig. 37D). Anteriorly the ventral and medial surfaces
are covered with large bumps (Text-fig. 376) . The anterior edge is rounded medially
but becomes sharp-crested laterally. The bone behind this edge is moderately thick
ISLE OF WIGHT, ENGLAND
75
Cl
4 cm
FIG. 36. Hypsilophodon foxii. Scapula and coracoid R583O, x i. A, lateral view
B, posterior view. For abbreviations see Text-fig. 34.
as is the postero-lateral edge. The latter edge has an irregularly pitted surface that
contacted the ends of the sternal sections of the first three dorsal ribs (Text-figs.
376, E). The postero-medial part of the sternum is very thin.
ll) THE FORELIMB
Humerus. As a result of the twisting of the shaft (Text-fig. 38) the moderately
expanded distal end of the humerus is set at an angle to the broader proximal end
that carries the anteriorly directed delto-pectoral crest (Text-fig. 38E). This crest
becomes progressively thicker distally towards the apex and the edge is rounded.
In the region of the apex the crest has a flat surface, facing antero-laterally (Text-fig.
38D), which becomes rounded more distally to merge with the shaft. The broad
proximal end with the delto-pectoral crest forms a longitudinally concave and
transversely twisted anterior surface (Text-fig. 386). Proximally the posterior edge
is thin but it becomes thicker and rounded, forming a slight ridge where it meets the
concave surface at the base of the delto-pectoral crest (Text-fig. 386). This ridge
continues on to the shaft, which is slightly oval in cross-section, and runs to the
ventral ulnar condyle. The anterior intercondylar groove is wider, deeper and
continues further along the shaft (Text-figs. 380, F) than the posterior intercondylar
groove (Text-figs. 386, F).
B
l.st.
FIG. 37. Hypsilophodon foxii. Sternum RIQ6, x i. A, anterior view; B, ventral view
with sternal section of dorsal ribs 1-3 displaced slightly ; C, lateral view right sternal
bone ; D, medial view of right sternal bone ; E, dorsal view with dorsal ribs 1-4.
Abbreviations : STM, sternum ; 1 dor r, dorsal ribs of left side ; 1 st, sternal segments of
left dorsal ribs ; r st, sternal segments of right dorsal ribs.
ISLE OF WIGHT, ENGLAND
77
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THE WEALDEN HYPSILOPHODON
B
head
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4cm
uc
FIG.
39. Hypsilophodon foxii. Humerus R583O, x i. Views and abbreviations as in
Text-fig. 38.
The shaft is more twisted in Rig6 (Text-fig. 38) and R582Q than it is in the smaller
R583O (Text-fig. 39). A comparable difference occurs between small, medium-sized
and larger humeri in Protoceratops (Brown & Schlaikjer 1940, fig. 27), so this is prob-
ably an age variation.
Ulna. The olecranon process is moderately well developed. The edges of the proxi-
mal end (Text-fig. 4oE) continue along the tapering shaft to the slightly expanded
and somewhat compressed distal end. The shaft is roughly triangular in cross-sec-
tion with a slightly concave medial surface which becomes more strongly so distally
(Text-figs. 400, E). The dorsal ridge (Text-figs. 4oD, E) continues to the thick and
rounded antero-lateral (radial) edge of the distal end. The rounded medial edge
(Text-figs 400, E) continues to the sharp postero-medial edge of the distal end. The
larger lateral edge continues as a well-defined edge on the outside of the shaft but
merges with the convex lateral face of the distal end. The middle part of the shaft
anterior to this ridge is slightly concave. Proximally there is a well-defined rugose
bump (u, Text-fig. 40) while distally there are two rugose areas (v, w, Text-fig. 40).
Swinton (1936, fig. 6) figured the ulna and radius of R583O ; he stated ( : 564) that
' the right ulna ... is preserved in perfect condition ' and gave the length of the radius
( : 566) and ulna ( : 565). However, the forearm on both sides is represented only by
proximal ends with that of the right radius mounted as a distal end. There are
several odd distal ends in the Hooley Collection that have been referred to R583O, but
none of these definitely fits on to the bones from the mounted skeleton.
ISLE OF WIGHT, ENGLAND
79
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THE WEALDEN HYPSILOPHODON
B
3cm
MC
FIG. 41. Hypsilophodon foxii. Manus Rig6, x i. A, dorsal view; B, ventral view.
Abbreviations: MC, metacarpal ; R, radius; U, ulna; 1-5, digits; i, intermedium;
ul, ulnare.
Radius. The articular surface on the proximal end is concave along one diagonal and
convex across the other (Text-fig. 4oE). The shaft is subtriangular in section. The
medial edge in the middle of the shaft is sharp but it is more rounded proximally
and distally. The lateral edge is very slight and gently rounded distally. Proxi-
mally there is a well-defined ridge with insertion markings (y, Text-figs. 403, C) while
distally there is a rugose area (x, Text-figs. 406, C).
Carpals. As noted by Hulke (1882), the wrist of the only complete manus (Text-fig.
41) is traversed by a seam of carbonaceous material that has obliterated the radiale
and distal carpals and bisected the ulnare. The dorsal surfaces of the ulnare and of
the adjacent intermedium of Rig6 are transversely concave (Text-fig. 41 A). As
preserved, it is impossible to determine the shape of the ulnare. The distal surface
of the intermedium is rounded transversely and probably articulated against the
distal carpals. The only trace of a distal carpal in Rig6 is a small corner which is
wedged medially between the ulnare and metacarpal IV (Text-fig. 41 A). The space
between the radius and metacarpals I and II may indicate the outline of the radiale.
Three rather distorted carpal bones were obtained from the disarticulated partial
manus of R2473 (Hulke 1873, pi. 18, fig. 3). These were matched with elements in
the Hooley Collection that have now been referred to R583O. The intermedium
corresponds closely with that of Rig6. The dorsal (Text-fig. 42a) and ventral
ISLE OF WIGHT, ENGLAND
81
1cm
FIG. 42. Hypsilophodon foxii. Intermedium 1^.5830, x 2. a, dorsal view ; b, lateral
view ; c, ventral view. Abbreviations : i, intermedium ; r, surface for radius ; u,
surface for ulna.
1cm
FIG. 43. Hypsilophodon foxii. Bone i, R583O, x 2. Views as in Text-fig. 42.
1cm
FIG. 44. Hypsilophodon foxii. Bone 2, 1^5830, X2. Views as in Text-fig. 42.
(Text-fig. 42c) surfaces are transversely concave with a polished surface. The surface
for the radius (r, Text-fig. 42) is concave but the remaining surfaces are convex
laterally and transversely. These slope slightly inwards as the ventral surface is
slightly smaller than the dorsal. The other two bones have been tentatively orien-
tated as shown in Text-figs. 43 and 44. The second bone is a cube with a trans-
versely concave dorsal surface and a similar but slightly smaller ventral surface
(Text-figs. 43a, c). The four articular sides are gently convex laterally and trans-
versely. This bone is either the radiale or the ulnare. The third bone has an
irregular shape (Text-fig. 44) without the polished surfaces of the intermedium and
the second bone ; in this it resembles the distal tarsals.
Hulke (1882, pi. 79) showed the space in the wrist of Rig6 bounded proximally by
the radius, intermedium and ulnare and distally by metacarpals I, II and III.
Abel (1911, fig. 12) in his reconstruction closed this space so that there is practically
no room for the radiale and none for any distal carpals. In contrast Steiner (1922,
fig. 17) put the radiale and two distal carpals in this space, with a small first distal
carpal and a second which is larger than the ulnare. Though Steiner's figure is
82
THE WEALDEN H YPSILOPHODON
>T3
11
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ISLE OF WIGHT, ENGLAND 83
'after Hulke', Hulke did not in fact indicate these details. Heilmann (1926, fig.
1 16) showed a radiale and the dotted outline of four distal carpals. In Thescelosaurus,
the two distal carpals are equal in size and much smaller than the ulnare (Gilmore
1915, fig. n). However, if the second bone (Text-fig. 44) is a distal carpal then
Steiner's reconstruction (1922) may be correct.
Metacarpals. The third metacarpal (Text-fig. 45) has a well-rounded proximal end
with well-defined lateral and medial edges. The shaft in cross-section is a circle
slightly flattened dorso-ventraliy. The muscle grooves on the distal condyles are not
strongly developed. There is no dorsal intercondylar groove and the ventral one is
shallow. The size and shape of the metacarpals are shown in Text-fig. 41. As pre-
served the distal ends of metacarpals I, II, and III are inclined at an angle of about
45 degrees to a line through the carpus. The proximal ends are inclined at a slightly
steeper angle and, though the area of contact is small, they are packed together. The
proximal end surface of metacarpals II and III are rounded and slope. Metacarpal
III is more slender and longer than metacarpal II. The proximal end of metacarpal
IV is triangular and the condylar region is in the same plane as the carpus. Meta-
carpal V as preserved is set at quite an obtuse angle to the others but in life this was
probably less marked.
Phalanges. The phalangeal counts of the first three digits are definitely 2, 3 and 4
respectively. The fourth metacarpal bears two phalanges and Hulke (1882) noted
that the distal half of the second of these was missing, as was the continuation of the
digit. Further development has exposed the ventral surface and the distal articular
surface is practically complete so that only a small part of this phalanx is missing.
Metacarpal V has a distal condyle but there is no evidence concerning the number of
phalanges. Gilmore (1915 : 600) tabulated the phalangeal formula of Hypsilophodon
as 2, 3, 4, 3, 2. This may be correct but the evidence from specimen Rig6 suggests
the formula 2, 3, 4, 3 (? +), I (? +).
iii) THE PELVIC GIRDLE
Ilium. In external view (Text-figs. 46A, 48, 49) the dorsal part of the ilium of
Hypsilophodon forms a thin and almost flat sheet of bone ; ventrally the bone is
much thicker and the surface curves outwards to the acetabulum. The dorsal edge
is sharp with a bevel running along most of its length. The posterior edge is rather
square in section with a rugose surface while the postero- ventral edge is sharp. The
anterior process of the ilium curves outwards with the lateral surface facing slightly
dorsally (Text-figs. 5oA, 5iA). This curvature enabled the process to clear the ad-
jacent ribs, provided a larger insertion area for part of the M. dorsalis trunci and per-
mitted a more fore-and-aft action of the M. ilio-tibialis i (Text-fig. 49, see Galton
1969). In addition the amount of antero-ventral curvature varies a great deal
between individuals ; the ilia can be arranged in a series that shows a progressive
increase in the degree of curvature (Text-figs. 4gA, 46A, 48A and 486). This varia-
tion is independent of the sacral type because only ~Rig6 has a pentapleural sacrum.
The outer edge of the ventral margin of the anterior process is rounded in all speci-
mens, but the inner edge is more variable. In Rig6 (Text-figs. 516, C) it is rounded
THE WEALDEN HYPSILOPHODON
\L
FIG. 46. Hypsilophodon foxii. Pelvic girdle Ri95, x i. A, lateral view ; B, acetabular
view of ischium. Abbreviations for Text-figs. 46-53. IL, ilium ; IS, ischium ; P, pubis ;
acet., acetabulum ; ant. proc. or a. p., anterior process ; brev. sh., brevis shelf ; il.,
surface for ilium ; is., surface for ischium ; obt. p., obturator process ; p., surface for
pubis ; ped., peduncle ; p. for., pubic foramen ; po. rod., post-pubic rod ; pre. proc.,
prepubic process.
ISLE OF WIGHT, ENGLAND
FIG. 47. Hypsilophodon foxii. Pelvic girdle R 195, x i. A, medial view ; B, acetabular
part of the ilium. For abbreviations see page 84.
86
THE WEALDEN H YPSI LOPHODON
ffl
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ISLE OF WIGHT, ENGLAND 87
and somewhat thicker than the rest of the process. In R2477a the inner part forms
a small ledge, which in RiQ3 (Text-figs. 506, C), R2477b and Ri95 (Text-fig. 47A)
shows a progressive increase in size. This ledge is mainly sharp-edged, though it
becomes reduced and rounded both anteriorly and posteriorly. This variation too is
independent of the sacral type. The slender anterior peduncle is triangular in section
with a sharp outer edge (Text-fig. 476) which disappears posteriorly. Its ventral
surface is broad and flat. It is broader in forms with the hexapleural sacrum (Text-
figs. 476, 5oC) than in those with the pentapleural type (Text-figs. 5iC, R2477b).
A prominent ridge runs along the medial surface (Text-figs. 47A, 506, 5iB) of the
anterior process. Ventral to this there is a longitudinal depression which is bordered
by the internal ledge mentioned above. Anteriorly another, much smaller, ridge
runs diagonally across the process. The thicker ventral region of the ilium bears the
rugose facets for the sacral ribs. The ledge below these sacral facets is sharp-edged
except for the section that lies internal to the ischiadic head of the ilium.
In all the ilia the first sacral rib fits on to the dorso-medially facing inner surface of
the peduncle. The facets for the remaining sacral ribs are more anteriorly placed in
Rig6 (Text-fig. 516) than they are in RiQ3 (Text-fig. 5oB) and RiQ5 (Text-fig. 47A),
both of which have a hexapleural sacrum. In both types there is a projecting edge
above facets 2 and 3. There is a similar edge above facet 4 in Rig6 but this facet
is only partly on the brevis shelf (Text-fig. 51). In Ri95 the whole facet is on the
brevis shelf and, anteriorly at least, there is a dorsal edge (Text-fig. 47 A). In RiQ3
there is no dorsal edge and the facet is obliquely inclined (Text-fig. 50), in contrast
to its much more vertical position in the others.
Pubis. The anterior end of the pubis is slightly flattened (Text-fig. 48A) . The outer
surface of the prepubic process is flat with well-developed striations (Text-fig. 49)
and the ventral edge is grooved. The function of the prepubic process has been
discussed elsewhere (Galton 1969, i_97oa) and it was suggested that the striations
were for a limb muscle (M. ilio-femoralis internus, M. pubo-tibialis or M. ambiens).
The ventral part of the stout acetabular region is laterally constricted and has a
rounded ventral edge (Text-fig. 526). The outer surface (Text-figs. 46A, 48A, 4gA)
is hollowed anteriorly into a shallow and approximately circular depression, but above
the obturator foramen this surface is convex. The inner surface (Text-fig. 47 A) is
slightly concave anteriorly, but it is convex at the root of the post-pubic rod. Pos-
teriorly the inner surface is strongly concave and funnels into the obturator foramen
(Text-fig. 47A). The postero-dorsal articular region is rough-textured and, except
anteriorly, is sharp-edged.
The obturator region is variable. Among the smaller individuals there is a notch
in Rigs (Text-fig. 47 A) but a foramen in Rig6 (Text-fig. 48 A) ; among the larger
individuals there is a notch in R5829 but a foramen in Ri93 (Text-fig. 4QA). It is
apparent that this is an individual variation. In those specimens where closure of
the notch has occurred, Rig6 shows no trace of a suture, while in Ri93 a suture is
visible on the lateral surface only ; in the latter specimen there is no evidence as to
when closure occurred (growth stages of the same individual would be needed for
this). Anteriorly the post-pubic rod has a dorsal sheet which may be variously
88
THE WEALDEN HYPSILOPHODON
CAUDI-FEMORALIS
BREVIS
ISLE OF WIGHT, ENGLAND 89
developed. In Rig6 it is absent (Text-fig. 48A) ; in RiQ5 it is small and faces
dorso-medially (Text-figs. 47A, 48A) ; in R582Q it is larger ; and in RiQ3 it is very
well developed (Text-fig. 49A). The edge is thickened in Rig3, forming with the
most anterior part a triangular area with an irregular surface.
Ischium. The ischium consists of a proximal head-region which is separated from
the large flat blade region by a constricted shaft (Text-figs. 46A, 48A, 4gA, 53).
Ventrally the head and shaft merge in Rig6 (Text-fig. 48A) and R5830 (Text-fig.
53E) but this junction becomes progressively more marked in the series R582Q,
Rig5 (Text-fig. 46A) and RiQ3 (Text-fig. 4gA). This is probably an individual
variation. The shaft is twisted so that the blade is at an angle of about 45 degrees
to the head. The inner surface of the blade therefore faces dorso-medially. This
surface and the internal surface of the head meet along a diagonal line which con-
tinues distally on to the base of the obturator process (Text-fig. 47 A). In relation
to the rest of the ischium the acetabular region is longer in Rig6 (Text-fig. 48A)
than it is in Ri93 (Text-fig. 4gA) or RiQ5 (Text-fig. 46A) and the ventral part is
lengthened to a corresponding degree. At the anterior end of the acetabular region
there is an internal expansion which is more strongly developed in Rig6 (Text-fig.
53D) than in RiQ5 (Text-fig. 466). The internal surface below this process forms a
shallow depression.
The dorsal edge of the shaft is rounded. Ventrally, the shaft is sharp-edged and
distally this edge curves abruptly downwards and inwards to form the obturator
process (Text-fig. 47A) . Posteriorly, the shaft gradually thins out as it merges into
the blade region. This continuation of the shaft tends to cross from the outer to
the inner edge because of the outward curve of the blade relative to the shaft. The
distal part of the ischium is straight, flat and blade-like. Anteriorly, on the dorsal
FIG. 49. Hypsilophodonfoxii. A, pelvic girdle RiQ3 in lateral view to show areas of attach-
ment of the individual muscles. Data also from Rig6 and 28707. Figure from Galton
(1969, fig. 6 ; see fig. 7 for stereo-photograph of pubis and ischium Ri93) in which the areas
are described. B, reconstruction of the pelvic region showing the lines of action of the
individual muscles. Data from Ri93, Ri96, R583O and 28707. Figure from Galton
(1969, fig. 4). Compare with Text-fig. 55.
The muscles have been abbreviated as follows :
ADD M. adductor femoralis IS-CAUD M. ischio-caudalis
AMB M. ambiens IS-TROC M. ischio-trochantericus
CA-FEM BR M. caudi-femoralis brevis LIG ligaments for holding head in
CA-FEM L M. caudi-femoralis longus acetabulum
DOR CA M. dorsalis caudae O A EXT M. obliquus abdominis externus
DOR T M. dorsalis trunci O A INT M. obliquus abdominis internus
FEM-T i, 2 & 3 M. femoro-tibialis i, 2 and 3 OBT M. obturator internus
F T E M. flexor tibialis externus P-I-F INT i dorsal part of M. pubo-ischio-
F T I M. flexor tibialis internus femoralis internus
G M. gastrocnemius P-I-F INT 2 ventral part of M. pubo-ischio-
IL-CAUD M. ilio-caudalis femoralis internus
IL-FEM M. ilio-femoralis P-TIB M. pubo-tibialis
IL-FIB M. ilio-fibularis R ABD M. rectus abdominis
IL-TIB i & 2 M. ilio-tibialis I (sartorius) and 2 TND tendon inserting on fibula
IL-TROC M. ilio-trochantericus TR A M. transversus abdominis
9o
THE WEALDEN HYPSILOPHODON
B
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4cm
ant. proc. ped acet. brev. sh.
FIG. 50. Hypsilophodon foxii. Ilium Ri93, x f . A, dorsal view ; B, medial view ;
C, ventral view. For abbreviations see page 84.
ISLE OF WIGHT, ENGLAND
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FIG. 51. Hypsilophodon foxii. Ilium Ri96, x i. A, dorsal view ; B, medial view ;
C, ventral view. For abbreviations see page 84.
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FIG. 55 . Hypsilophodonfoxii. Femur showing the areas of attachment of the limb muscles,
mainly RiQ3 with data from Ri96 and R583O. From Galton (1969, fig. 10 ; see fig. 8
for stereo-photograph of femur of Ri93) in which the areas are described. A, posterior
view ; B, lateral view ; C, anterior view ; D, medial view. Abbreviations : gr. troc.,
greater trochanter ; les. troc., lesser trochanter ; 4th troc, fourth trochanter. For
abbreviations of muscles see Text-fig. 49.
surface of the blade, there is a definite depression above the obturator process
(Text-fig. 47A). In Rig6 alone, a groove is present along the upper region of the
outer surface of the blade. The dorsal edge of the blade is sharp. Ventrally, it is
also sharp-edged, but it thickens distally to form an almost square edge. The distal
end of the blade is swollen, with a rugose surface (Text-fig. 53E).
IV) THE HINDLIMB
Femur. The shaft of the femur is twisted so that the outer surface at the proximal
end becomes the anterior surface more distally (Text-fig. 54D) . The lesser trochanter
is somewhat triangular in section (Text-fig. 54E) and is separated from the greater
trochanter by a short cleft (Text-fig. 54!)). The lesser trochanter is set slightly
away from the external surface of the greater trochanter but gradually merges with
the shaft more distally (Text-fig. 54A). Proximally the outer surface of the greater
trochanter is flat but near the posterior edge there is an ' S '-shaped ridge that sep-
arated the insertion area of the M. pubo-ischiofemoralis internus i from the more
posterior M. ilio-trochantericus (Text-fig. 556 ; see Galton, 1969 in which the areas
of muscle attachment on the femur of Ri93 are discussed). Running diagonally
across the posterior face of the head is a strongly concave depression (Text-figs.
546, E) which is bounded internally by a stout ridge.
96 THE WEALDEN HYPSILOPHODON
Behind the head the neck and shaft form an acute though rounded edge which is
continuous with the sharper outer edge of the pendant fourth trochanter pointing
posteriorly. The large fourth trochanter probably improved the leverage of the
M. caudi-femoralis brevis (from brevis shelf of ilium ; Text-fig. 49) during the first
half of femoral protraction (see Galton 1969). The outer surface (Text-fig. 55 A) of
the fourth trochanter is gently concave, the curve continuing that of the adjacent
shaft. In internal view (Text-fig. 546) most of the shaft is convex, but at the base
of the fourth trochanter there is a depression, quite deep (Ri93, Text-fig. 55D ;
Ri95, R2477b) or very shallow (Ri96, R582g, R5830, Text-fig. 546), which probably
served for the insertion of the caudi-femoralis longus muscle (Text-fig. 550 ; see
Galton 1969). The shaft is narrowest just above the fourth trochanter where its
cross-section is roughly quadrilateral with rounded edges. Below this it is roughly
circular with a slight antero-posterior flattening. The anterior face (Text-fig. 54D)
forms a progressively flatter convex curve and there is practically no anterior inter-
condylar groove (Text-fig. 54F). Posteriorly the outer condyle is almost as large
as the inner and the surface becomes concave towards the base of the condyles with
a deep but quite wide intercondylar groove (Text-figs. 546, F).
Tibia. The proximal end is only moderately expanded (Text-fig. 56E) with a flat
and slightly inclined surface (Text-fig. 566). The proximal condyles (Text-fig. 566)
are rounded and approximately equal in size and they shortly merge with the
convex shaft. The outer condyle bears a much smaller condyle on its antero-
lateral face (Text-fig. 56A) against which the fibula fitted. The cnemial crest of
the tibia is small and forms a rounded edge (Text-fig. 56D) which is continued some-
what diagonally down the shaft, passing internally to merge with the base of the
inner malleolus (Text-fig. 56D). The depression between the distal malleoli con-
tinues along about a quarter of the shaft (Text-fig. 56D). In anterior view (Text-
fig. 56D) the medial part of the inner malleolus is convex while the lateral part below
the intercondylar groove is transversely concave and more obliquely inclined. In
posterior view (Text-fig. 566) there is a distal sharp edge backing the malleoli. The
surface above the outer malleolus is convex but that above the inner malleolus is
concave.
The shaft of the tibia is basically triangular in section but the sharpness of the
edges varies. In Ri96, R752 and R5830 (Text-fig. 56) these edges are rounded apart
from that above the outer malleolus. In Ri99 (Hulke 1882, pis. 80 and 81) the edges
are more marked and the edge above the outer malleolus is much sharper and forms
a step. The edge visible in anterior view above the inner malleolus also varies. In
Ri93, Ri99 and R5830 (Text-fig. 56D) it is smooth, forming a gentle and continuous
curve on the shaft. In Ri96 and R5829 this edge, about a third up, is considerably
enlarged and swollen, the area being covered with well-developed surface markings.
All of these seem to be individual variations.
Fibula. Only in R5830 are both ends well preserved. Swinton (1936 : 568) noted
that the right fibula of this specimen was complete and figured it as such (Swinton
1936, fig. 7) but the middle two-thirds is restored in plaster. The proximal surface
is transversely rounded and articulated during adduction with the groove on the
ISLE OF WIGHT, ENGLAND 97
outer condyle of the femur. The concave curve of the medial surface (Text-fig.
56E) continues on to the proximal third of the shaft but below this the shaft is oval
in cross-section. In S.M. 4127 the upper half of the fibula is slightly curved, with
a concave anterior outline, and it is set at a slight angle to the distal half. Distally
the fibula is backed to a progressively greater extent by the outer malleolus of the
tibia. This part of the fibular shaft in Ri93 is laterally expanded with a sharp
inner edge ; the anterior surface is slightly concave longitudinally while the posterior
surface against the tibia is flat. The outer edge is gently convex and this, together
with the anterior surface, sweeps out to the distal head ; the latter is rounded in
outline apart from the flat area against the tibia. The edges of the distal end are
rounded but the end surface is flat and fitted against the calcaneum.
Astragalus. This consists of two sheets of bone, one capping the distal end of the
tibia (Text-fig. 57E), the other an ascending process that wraps round part of the
anterior surface of the tibia (Text-figs. 56D, G). The ascending process ends in a
tooth-like structure set out in slight relief from the adjacent bone (Text-figs. 56D,
57A, B). Below this ' tooth ' the ascending process is very thick and continues pos-
teriorly as a broad ridge across the concave proximal surface (Text-fig. 57A) while
medial to this ridge there is a large depression. This proximal surface was closely
applied to the distal end of the tibia (compare Text-figs. 57A, 56F). The astragalus
thins posteriorly and ends in a sharp edge (not visible in Text-fig. 566) closely
applied to the adjacent surface of the tibia. Though there is a gap below the inner
corner of the fibula in R5830 (Text-fig. 56D) this area in Rig6 is filled by bone that
appears to belong to the astragalus. This is confirmed by the presence of a broken
surface on the external proximal corner of the astragalus of R5830 (Text-fig. 57D).
The shape of this part of the bone is indicated by the adjacent surfaces of the fibula
and calcaneum.
Calcaneum. The outer surface (Text-fig. 56A) is gently concave and forms a definite
edge, indented in several places (Text-fig. 56E), with the curved antero-distal surface
for distal tarsal i. The proximal surface against which the fibula fitted is concave
(Text-fig. 57A), the depression continuing medially on to the inner surface (Text-fig.
576) . The posterior surface for the outer malleolus of the tibia is a large depression
(o, Text-figs 576, D) which forms a thin and sharp edge with the outer edge (Text-fig.
57D). This obliquely inclined depression forms sharp diagonal edges with the prox-
imal (Text-fig. 57A) and distal (Text-fig. 57E) surfaces. The medial view (Text-,
fig. 576) shows five surfaces, three of which I have designated (f, d.2 and o). The
surface (a) for the main part of the astragalus is flat and above this there is a concave
surface (e) for the dorso-laterally directed process of the astragalus. A medially
directed corner (see Text-fig. 57A) is formed by the contact edges of surfaces e, f and
o. However, the antero-distal part of the depression (e) is also continuous with those
surfaces for the fibula (f) and tibia (o).
Distal tarsal i. This is an irregularly flattened plate of bone with rounded edges
which are indented in several places. Most of the proximal surface (Text-fig. 57F)
with which the astragalus articulated is slightly convex, apart from a central concave
98
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FIG. 58. Hypsilophodon foxii. Pes Ri9&, x f . A, dorsal view ; B, ventral view with
details of metatarsal V from SM 4127. Abbreviations : MT, metatarsal ; 1-5, digits.
region in the ventral half. Most of the distal surface (Text-fig. 570) is flat with
radiating surface markings ; the proximal end of metatarsal III articulated with the
lateral two-thirds of this surface. The ventro-medial corner is bevelled to form a
distinct depression (Text-fig. 57G). A well-developed boss on metatarsal II (Text-
fig. 57H) fitted into this depression while the remainder of the lateral part articulated
with the flat surface of this distal tarsal (cf. Text-figs. 570, H).
Distal tarsal 2. This is a rather irregular wedge-shaped bone. The proximal
(Text-fig. 57F) and distal surfaces (Text-fig. 570) are concave. The inner surface
(d.i Text-fig. 57M) is markedly concave and fitted against the lateral surface of
ISLE OF WIGHT, ENGLAND 101
distal tarsal i. This depression continues a short distance on to the dorsal surface
(Text-fig. 57 J) The outer and ventral surface (Text-fig. 57 J) form a continuous and
obliquely inclined curve progressively increasing with width (Text-fig. 57M). The
reduced fifth metatarsal articulated with the wide ventral part of this surface.
Metatarsals. The relative length of the metatarsals varies, but metatarsal III is
always the longest and stoutest with metatarsal I about half as long. In 1^5830
metatarsals II and IV are approximately equal but in all other specimens metatarsal
II is slightly shorter than metatarsal IV. The anterior (dorsal) surface of the meta-
tarsus is transversely convex (Text-figs. 57!!, 58A) with well-marked corners which
become more rounded distally. Proximally the metatarsals are expanded antero-
posteriorly with the anterior face sweeping upwards so that a deep articular surface
is formed, especially large in metatarsals II and III (Text-fig. 57H). The posterior
surface of the metatarsus is concave (Text-figs. 57!!, 586), although the individual
metatarsals are gently convex and becoming more strongly curved distally.
The distal articular condyle of metatarsal I is not reduced (Text-figs. 57]", 58) and
the adjacent part of the shaft is subtriangular in cross-section. The shaft becomes
more compressed so that the proximal part is thin and flat with almost no proximal
articular surface. The amount of the first metatarsal visible in ventral view (Text-
fig. 58B) progressively decreases because the flattened proximal part wraps round
on to the dorso-lateral surface of the second metatarsal (Text-fig. 58A). The proxi-
mal end of metatarsal II is bioconcave with a well-developed bump towards its rear
surface (Text-fig. 57!!) which fitted against the step on distal tarsal i. The medial
surface is rounded beyond the end of metatarsal I, while the flat lateral surface
against metatarsal III is reduced distally so that the shaft becomes almost circular
in section. The proximal end of metatarsal III has an irregular surface which
fitted against distal tarsal 2. The cross-section of the shaft near the distal end is a
dorso-ventrally flattened circle. The proximal end of metatarsal IV is concave,
with a well-developed bump on each of the inner corners (Text-fig. 57H), and it
contacted distal tarsal 2. Most of the shaft is somewhat triangular in outline with
a sharp lateral edge formed by the junction of the gently convex anterior and
posterior surfaces. The distal half diverges laterally and also slightly posteriorly
from metatarsal III. In ventral view (Text-fig. 586) there is an edge on the medial
margin which gradually passes laterally until it merges with the roots of the outer
condyle. The shaft internal to this ridge is convex but external to it is gently con-
cave. This ridge is also well developed in R2OO and S.M. 4127 but it is absent in
R5830 ; its development is probably related to size. Metatarsal V is reduced to a
splint which is well preserved in S.M. 4127 (basis for Text-fig. 586). The proximal
end is transversely expanded to form a head, oval in section and with a rounded end
which articulated with the posterior surface of distal tarsal 2. The distal end has
an obliquely inclined articular surface but no phalange was found.
Phalanges. The proximal ends of the first and last phalanges of each digit do not
bear a well-developed dorsal process as do the other phalanges (Text-fig. 58A) . These
processes appear to be less strongly developed in R5830 than they are in Rig6 ; this
is probably due to the difference in size. The proximal ends (Text-fig. 57N) are
102 THE WEALDEN H YPSILOPHODON
concave with a median ridge so that two depressions are formed. These are shallow
in the first and ungual phalanges (Text-fig. 5yK) but are well developed in the others.
The lateral muscle grooves are well developed on the distal condylar head (Text-fig.
57N). The central depression is continued dorsally on to the non-articular part
and the resulting cavity received the dorsal process of the next phalanx. The un-
gual phalanges are slender (Text-figs. 57K, 58) and the grooves for the claw are well
developed.
e) Dermal armour
A few thin sheets of bone are present close to the skull of specimen R2477- Hulke
(1874, pi. 3, fig. i) figured these and regarded them as thin scutes, noting that they
were 'irregularly polygonal' in outline with one surface granular, the other smooth
and furrowed by a vascular net. In a later paper (1882) they were figured but neither
labelled nor mentioned. Nopcsa (1905, fig. 4) figured them and noted ( : 205) that
Hypsilophodon was ' clad with a thin but well developed dermal armour consisting of
comparatively large yet thin and flat, feebly punctured plates'. He also noted that
they showed the same feebly grooved sculpture and could not be referred to any part
of the endoskeleton. Romer (1956 : 428) noted that ' Hypsilophodon had a paired
row of thin dorsal plates presumably retained from the thecodont ancestors'.
The thin overlapping plates of bone were shown by Nopcsa (1905, fig. 4) but it is
impossible to determine their original shape as all the edges are broken. The plates
lie lateral to the distal parts of the dorsal ribs of individual ' a ' and very close to a
skull that probably belongs to another individual (Hulke 1874, pi. 3, fig. 1,2; Galton
1967, photograph fig. 23). However, it is not certain to which individual the plates
belong. Consequently there is no evidence to show that the plates were paired or
dorsal in position. Both surfaces are rough, lacking the smooth finish of other
bones, with various small and irregularly shaped depressions.
It is possible that these plates formed part of a dermal armour. However, if
such were the case it is surprising that they have not been preserved in any of the
other specimens. In Ri94 there is a similar plate, about a square inch in size, but
it is so eroded that it could be anything. It is particularly surprising that these
elements were not preserved in RigG because this skeleton is so complete in all other
respects. Nopcsa (1905) could not identify these plates as any part of the endo-
skeleton but they could be the remains of a damaged sternum. Consequently,
although they may well represent dermal armour, further material is needed to
confirm this identification. Dermal armour is present in most thecondontians but
Hypsilophodon is the only ornithopod in which dermal armour has been reported.
In stegosaurs and ankylosaurs dermal plates formed a strong armour.
V. CAMPTOSAURUS VALDENSIS-A. LARGE HYPSILOPHODON FOXII
Lydekker (1888) noted that the damaged left femur Ri67 (PI. 2, fig. 4) might,
because of its greater size, represent a species distinct from Hypsilophodon foxii.
He also catalogued a small mandibular ramus Ri8o as that of a young I guano Aon
(Owen 1864, pi. X figured it as this). In the same year he stated (i888a) that this
ISLE OF WIGHT, ENGLAND 103
ramus might belong to a smaller adult form, allied to Laosaurus or Dryosaurus, in
which case the femur Ri67 might belong to the same form. Subsequently (1889)
he noted that the femur was very similar to that of Camptosaurus leedsi from the
Oxford Clay, which is itself very similar to the femur of the North American Campto-
saurus. Because there was no other evidence of a Hypsilophodon of these dimensions
he made the femur Ri67 the type of a new species, Camptosaurus valdensis, to which
he provisionally referred the mandibular ramus. He listed the femur and jaw as
Camptosaurus valdensis in the supplement to his catalogue (1890).
Gilmore (1909) noted that the fourth trochanter of Ri67 was on the proximal half
of the shaft and he opined that, because in the American Camptosaurus it is on the
distal half, this femur must be distinct from Camptosaurus. There are other differ-
ences between the two. The lesser trochanter of Ri67 is not expanded antero-
posteriorly and the cleft separating it from the greater trochanter is shallow and ends
level with the middle of the head. In the American Camptosaurus (Gilmore 1909,
fig. 42-1) and C. leedsi (Lydekker 1889, fig. 3) the trochanter is expanded and the
cleft is deep and ends level with the bottom of the head. In addition, Camptosaurus
has a well-developed anterior intercondylar groove which is absent in Ri67.
In the characters cited (the position of the fourth trochanter, the shape of the
lesser trochanter, the depth of the cleft between the lesser and greater trochanters
and the absence of a marked anterior intercondylar groove) the femur Ri67 agrees
with those of Hypsilophodon (Text-figs. 54, 55). Consequently this femur is regarded
as belonging to the genus Hypsilophodon.
Lydekker (1888, 1889) emphasized the large size of the femur Ri67 in comparison
with those of Hypsilophodon foxii ; Swinton (19366) stated that it is half as large
again as any femur known in that genus. The total length of Ri67 is unknown but
the minimum distance between the proximal end and the distal surface of the fourth
trochanter is 108 mm (see Text-fig, if). The distance in R5829 (the largest femur
generally regarded as Hypsilophodon foxii) is 87 mm, so Ri67 is not quite 25 per cent
as large again. The femur of Ri67 is therefore regarded, not as representing a new
species but, on the contrary, as a femur of Hypsilophodon foxii from the largest
individual hitherto found, which would have been about 7-5 ft or 2-28 m long.
The teeth of the mandibular ramus (Ri8o) mentioned above resemble the corre-
sponding teeth of Iguanodon atherfieldensis (see Hooley 1925). Therefore this
ramus is referred to a young Iguanodon, following Owen (1864) and Lydekker (1888).
This was the only other specimen referred to Camptosaurus valdensis ; consequently
the genus Camptosaurus is not so far represented in the Wealden of the Isle of Wight.
VI. ASPECTS OF CRANIAL ANATOMY
a) The foramina of the braincase
The foramina for the olfactory, optic and trochlear nerves (I, II and IV) are not
preserved because the more anterior part of the braincase was cartilaginous. The
same is true of the dorsal boundary of the large foramen for the oculomotor nerve
III. The dorsal edge of the parasphenoid is concave and probably formed the ventral
border to this foramen (III, Text-fig. 6oA). The resulting foramen bears exactly the
I04 THE WEALDEN HYPSI LOPHODON
same relationship to the surrounding structures as does the foramen for the oculo-
motor in hadrosaurs (see Ostrom 1961, fig. 12).
Trigeminal foramen (V, Text-figs. 46, 9, 6oA). This large foramen is enclosed
mainly by the prootic but anteriorly it is bordered by the laterosphenoid. On the
lateral surface of the laterosphenoid there is a short groove which passes antero-
dorsally from the trigeminal foramen (Text-figs. gA, 6oA). The deep ophthalmic
ramus (Vx), a sensory tract from the snout that branches off close to the braincase,
probably ran in this groove. In hadrosaurs there is another groove running ven-
trally for the maxillary and mandibular rami (V2 and V3) ; in Hypsilophodon there
is no well-developed groove but the common course of these two rami is faintly
discernible, probably passing postero-ventrally to the edge of the step running from
the base of the basipterygoid process (Text-figs. 46, 6oA). There is a slight depres-
sion on the posterior face of this edge which was probably for those two rami. The
maxillary ramus (V2) presumably passed forwards above the base of the pterygoid
process while the mandibular ramus (V3) continued ventrally ; these routes are visible
in hadrosaurs (Ostrom 1961) but not in Hypsilophodon.
Abducent nerve (VI). The abducent of hadrosaurs arises from the floor of the
metencephalon and passes through bone in a long canal, part of which is lateral to the
sella turcica, to emerge through the oculomotor foramen (Ostrom 1961). The posi-
tion appears to be the same in Hypsilophodon but the part in the lateral wall of the
sella turcica is not enclosed by bone. The exit of a canal into this part of the sella
turcica is visible on both sides in R2477 but its entrance into the inner wall of the
braincase cannot be located.
Facial nerve (VII) passes through a small foramen in the prootic (Text-figs. 9, 6oA).
Leading ventrally from this there is a groove which continues ventrally medial to the
groove already mentioned for V2 and V3. The anterior branch (palatine ramus) of
the facial nerve presumably ran in this groove and then passed ventral to the
basipterygoid process.
In medial view (Text-figs. gB, C) the posterior part of the prootic of Hypsilo-
phodon shows a process which meets a corresponding process of the opisthotic. The
anterior opening bounded by the prootic was probably for the auditory nerve (VIII).
The posterior opening bounded by the opisthotic is interpreted as a combined
foramen lacerum posterius (for cranial nerves IX, X and XI) and jugular foramen (for
the internal jugular vein). This common opening is separated from the internal
auditory meatus, the inner ear cavity and the fenestra ovalis by a thin bony partition
(Text-fig. gA). A similar partition is mentioned by Gilmore (1914) in Stegosaurus.
Medially (Text-fig. gC) the three cranial nerves share a single opening but more
laterally there is a small tunnel in the posterior wall which forms a separate exit
visible in lateral view (Text-fig. gA). This posterior opening was probably for the
accessory nerve (XI) while the glossopharyngeal (IX) and vagus (X) nerves remained
in the main foramen. In hadrosaurs the foramen for the accessory nerve is com-
pletely separate from the other two (Ostrom 1961). The foramen for the hypoglossal
nerve (XII) is completely enclosed by the opisthotic (Text-figs. gA, C).
ISLE OF WIGHT, ENGLAND 105
In medial view (Text-figs. gB, C) there are three features of the braincase which
are not associated with cranial nerves : the fossa subarcuata, the lagenar recess and
the opening for the vena cerebralis posterior. The sutural region between the
supraoccipital and the prootic is excavated to form a large and tapering tunnel. A
similar structure is present in Plateosaurus , interpreted by Janensch (1936, fig. 3) as
the fossa subarcuata. The structure of the middle ear of Hypsilophodon cannot be
determined but was probably similar to that of hadrosaurs as described by Ostrom
(1961). In Hypsilophodon only part of the lagenar recess is visible ; this forms a
concave depression on the postero-ventral part of the prootic ventral to the fenestra
ovalis. On the opisthotic immediately above the medial opening of the hypoglossal
nerve there is an opening (f, Text-figs. gB, C) which leads into a small tunnel. Jan-
ensch (1955) labelled a similar opening in Dysalotosaurus as the vena cerebralis
posterior ; he had discussed this identification in an earlier paper (1936).
b) The par occipital process and the post-temporal fenestra
What appears to be part of the suture between the exoccipital and the opisthotic
is visible on the medial surface of R84i8 (Text-fig. 96). The suture forms a clearly
defined edge which, because the bone surface is well formed with faint markings, is
not the result of displacement along a crack. Consequently it appears that in Hypsi-
lophodon the exoccipital portion is restricted to the lateral part of the occipital con-
dyles. The part through which the foramina pass is part of the opisthotic as is the
paroccipital process.
Langston (1960) described a fragmentary skull of a hadrosaur in which the main
occipital part of the paroccipital process appeared to be formed by the exoccipital.
Overlapping this anteriorly but not extending to its distal end was a smaller process
formed by the opisthotic. The tapering part of the prootic overlapped the base of
the opisthotic anteriorly. However, the form of the paroccipital process was quite
normal and it should be noted that several of the suture lines are shown dotted.
Langston stated that in camptosaurs the opisthotic does not form part of the par-
occipital process. Regarding the position in Camptosaurus Gilmore (1909 : 207)
stated that ' the exoccipital and opisthotic are firmly coalesced, and there is no indi-
cation of the position of the suture that evidently was early obliterated'. He
regarded the portion forming the occipital condyle as exoccipital and the rest, in-
cluding the paroccipital process, as opisthotic. Janensch (1955) considered that in
the hypsilophodont Dysalotosaurus all the bone behind the prootic was exoccipital
with no mention of the opisthotic. Information from other specimens is needed
to ascertain whether the paroccipital process of ornithischians is usually formed by
the opisthotic or by the exoccipital.
In hadrosaurs the very small post-temporal fossa is bordered ventrally by the
paroccipital process (see Langston 1960) while in Hypsilophodon it is totally enclosed
by the paroccipital process (Text-figs. 76, 8, 96). Leading antero-medially and
dorsally from the resulting foramen is a slight depression which soon disappears.
However, more anteriorly on the side of the supraoccipital there is a well-defined
groove which passes medial to the parietal to enter the braincase (Text-fig. 60 A).
106 THE WEALDEN HYPSI LOPHODON
The anterior groove and the posterior depression are in line, bearing the same rela-
tionship to the edge of the supraoccipital, so it is reasonable to conclude that the
same structure occupied both. The resulting course rules out a nerve so this
structure must have been a blood vessel, presumably the vena capitis dorsalis. Cox
(1959) pointed out that in Sphenodon (O'Donoghue 1929) and Lacerta (Bruner 1907)
the vena capitis dorsalis, which drains the muscles of the spino-occipital region, runs
anteriorly through the post-temporal opening. Just before it enters the braincase
it receives an anterior factor, the sinus-like vena parietalis, from above the parietal
bone. In Lacerta the vena capitis dorsalis passes through the posterior end of the
great parietal fissure (between the parietal and the prootic) to join the vena cerebralis
media (Bruner 1907). In Hypsilophodon the route is similar though it is between
the parietal and the supraoccipital. On the parietal there is a slight depression,
running antero-dorsally from the projection on the ventral edge (Text-fig. 6oA),
which was probably for the vena parietalis. Consequently a vena capitis dorsalis
ran along the lateral surface of the supraoccipital and the paroccipital process of
Hypsilophodon. The presence of this vessel confirms the identification of the fora-
men in the paroccipital process as the remnant of the post-temporal fossa.
c) The eye
The orbit of Hypsilophodon (Text-fig. 3) is large and the interorbital septum, which
was presumably present, was very high. As reconstructed the sclerotic ring is also
large though, as noted above, it may have been slightly smaller than shown. The
orbital surfaces of the pref rental, frontal, postorbital and jugal are all inclined rather
obliquely (Text-figs. 4A, 5 A, 6B). In addition the dorsal edge formed by the pre-
frontal, frontal and postorbital is cut back, forming a sharp and well-defined edge to
the orbit. All these features indicate that the eye of Hypsilophodon was large and
filled the orbit as in birds.
In dorsal view (Text-fig. 56) the striking features about the skull are the largeness
of the orbits and the narrowness of the frontals. The eye of Hypsilophodon would
have projected slightly and this is confirmed by the shape of "the supraorbital that
curves out laterally. The rather oblique configuration of the orbit in dorsal view
(Text-fig. 56) suggests that the fields of view overlapped slightly when the eyes
looked more anteriorly. Certainly in anterior view (Text-fig. 7A) much of the pos-
terior part of the orbit is visible.
In Hypsilophodon the sclerotic ring is only slightly convex in transverse section.
Underwood (1970) notes that this form indicates that there was a sharp change
of curvature between the posterior and anterior segments of the eye, with a well-
developed sulcus, indicating good powers of accommodation and diurnal habits.
Underwood also states that the diameter of the inner and outer edge of the ring
gives an indication of the relative size of the cornea. An inner diameter of about a
third or less of the outer is a fair indication of diurnal habits. This cannot be
accurately applied to the ring of Hypsilophodon because the reconstruction is rather
tentative with regards to these measurements. However, it seems likely that Hypsi-
lophodon had quite good powers of accommodation and was diurnal in its habits.
ISLE OF WIGHT, ENGLAND 107
The form of the orbit might suggest that Hypsilophodon was arboreal but, as
discussed below, Hypsilophodon was not specifically adapted for tree-climbing and
was probably cursorial. Heterodontosaurus (Crompton & Charig 1962), Parkso-
saurus (Parks 1926, Galton in press) and Dysalotosaurus (Janensch 1955) are other
ornithopods with large orbits and these, as shown by the proportions of their hind-
limbs, were probably also fast runners. Outside the Ornithischia the closest approach
to the relative largeness of the orbits is in Omithomimus (see Romer 1956, fig. 8iA),
a definitely cursorial animal.
The function of the sclerotic ring must be considered. Edinger (1929) showed by
experiments on the lizard Ophisaurus that the plates do not change their relative
position and, consequently, do not aid in the dilation of the pupil as has been sug-
gested. However, they must aid in supporting and maintaining the shape of the
eyeball. Ostrom (1961) considered it unlikely that this was their function because
forms with sclerotic rings occupy an extremely wide range of habitats and, in
addition, related forms without rings may occupy the same habitat as forms with
them. He therefore concluded that the function of these structures has not yet been
determined. Colbert (1962) noted that the function of the sclerotic ring was de-
batable. However, Walls (1942) discussed the function of the sclerotic ring as
follows. The typical sauropsid sclera consists mainly of a cartilaginous cup of which
the open rim extends quite close to the edge of the cornea. The remaining zone of
the sclera is occupied by the sclerotic plates which are lacking only in crocodilians
and snakes. Because the plates are flat or concave they do not continue the
rotundity of the equatorial sclera smoothly into the sharper curve of the cornea.
On the contrary the sclero-corneal junction is depressed or concave to form a broad
annular sulcus. Walls (1942 : 275) stated that 'the production of a sulcus is the
whole meaning, physiologically, of the sauropsidan ossicular ring. It stiffens the
concavity against the force of the intraocular pressure which, if unresisted, would
evaginate it. This pressure rises slightly during accommodation, which it does not
do in fishes, amphibians or mammals.' He noted that the presence of a sclero-
corneal sulcus resulted in the ciliary body touching the lens. The striated ciliary
muscles are arranged in such a way that they cause the ciliary process to squeeze the
lens so that its anterior surface becomes more rounded (for figures showing the
mechanism of accommodation in the eyes of reptiles and birds see also Young 1962,
figs. 218, 293).
The sclerotic ring is absent in crocodiles, snakes and mammals. Walls (1942)
suggested that the loss of the sclerotic ring in modern crocodiles can be attributed to
the adoption of nocturnal habits in which the images are crude and accommodation
useless. The eye of snakes, when compared with that of lizards (see Young 1962,
fig. 238), shows that many structures have been lost and that there are various
improvisations to give the same results. Walls (1942) suggested that a burrowing
mode of life in the ancestral snake led to the loss of many structures in the eye so
that when snakes subsequently came above ground they had to adapt what was left.
This theory has been disputed but a phase of nocturnal existence would be adequate
to explain the loss of the sclerotic ring. In mammals accommodation relies on the
elasticity of the lens capsule to supply the actual force of accommodation. Walls
108
THE WEALDEN H YPSILOPHODON
M.p.temp.
M.extsup.
M.ext.med.
M.ext.prof.
— M.dep.mand.
mesokinetic axis & joint metakinetic
P i°int &
F XvT^-^j^-A. axis
FIG. 59. Hypsilophodonfoxii. Skull R2477, x i. A, the lines of action and moment arms
of the jaw muscles. Abbreviations for the muscles in Text-figs. 5QA and 60 :
M. add. m. post. M. adductor mandibulae
posterior
M. dep. mand. M. depressor mandibulae
M. adductor externus medialis
M. adductor externus
profundus
M. adductor externus
M. ext. med.
M. ext. prof.
M ext. sup.
M. prot. pt. M. protractor pterygoidei
M. pt. dor. M. pterygoideius dorsalis
M. p. temp. M. pseudotemporalis
M. pt. vent. M. pterygoideus ventralis
Pt. D. M. pterygoideus D (anterior
division of M. pt. dor.)
Pt. V. M. pterygoideus V (anterior
division of M. pt. vent.)
superficialis
B, the regions of movement in the skull, lateral view ; for discussion see page no ; C, the
regions of movement in the skull roof. Abbreviations : mes j, mesokinetic joint ; met j,
metakinetic joint ; sliding artln., sliding articulations. For abbreviation of skull bones
see page 109.
ISLE OF WIGHT, ENGLAND
109
B
M.p.temp.
:\— M.ext.sup.
M.ptvent.
FIG. 60. Hypsilophodon foxii. Details of the skull R2477, x i. A, braincase in lateral
view to show areas of muscle attachment and routes of nerves and blood vessels, compare
with Text-fig. 46 ; B, area of origin of M. adductor externus superficialis, compare with
Text-figs. 3, 4A ; C, vertical section through the lachrymal and maxilla taken along line
below middle of lachrymal ; D, medial view to show lines of action of pterygoideus mus-
culature, compare with Text-figs. 5 A, loB and PL 2, fig. 2. Abbreviations : ant. cav.,
antorbital cavity or fossa ; ant. f., antorbital fenestra ; I.e., lachrymal canal ; v, cap. d.,
vena capitis dorsalis ; v. par., vena parietalis ; III, oculomotor foramen ; V, trigeminal
nerve ; Vj, ramus ophthalmicus ; V2, ramus maxillaris ; V3, ramus mandibularis ;
VII, facialis nerve ; VIIpa] ramus palatinus. For abbreviations of muscles see page 108.
no THE WEALDEN HYPSI LOPHODON
(1942) noted that mammals originated from forms with small bodies which were
almost certainly nocturnal.
It is apparent that the sclerotic ring of dinosaurs, as in other sauropsids, was
essential for accommodation because it maintained the shape of the sulcus. The
absence of the ring in animals occupying the same terrestrial habit as others with it
can be explained by a nocturnal phase in the ancestry of the former.
d) Jaw musculature
Apart from the cranial crests and specializations associated with the large dental
batteries the hadrosaur skull is basically similar to that of Hypsilophodon. Ostrom
(1961), who used about 80 skulls, gave a detailed account of their cranial musculature.
By using this account in conjunction with the skull of R2477 a good idea of the jaw
musculature of Hypsilophodon can be obtained. The inferred lines of action of the
muscles are shown in Text-figs. 59, 6oD. Ostrom (1961) followed the tripartite
division of the mandibular musculature established by Luther (1914) and Lakjer
(1926). These divisions are separated on their function and innervation rather than
on their position. The adductor mandibulae group, which includes the superficial
muscles of the temporal region, functions to close the jaws. Medial to this in forms
with a kinetic skull is the constrictor dorsalis group which elevates the maxillary
segment. The last group, the intermandibular muscles, aids in swallowing and
respiration. The remaining muscle concerned with jaw movement is the M. depres-
sor mandibulae - a branchial muscle which acts to open the lower jaw.
i) ADDUCTOR MANDIBULAE GROUP
The adductors are separated into external, internal and posterior masses according to
their relationship with the branches of the trigeminal nerve (Luther 1914, Lakjer
1926 ; see Ostrom 1961 for details).
M. adductor mandibulae externus. This is the most variable of the adductor muscles
in fishes, amphibians and reptiles and is typically divided into three parts : partes
superficialis, medialis and profundus.
Pars superficialis. Origin : on the lateral surface of the squamosal of Hypsilo-
phodon, anterior and dorsal to the head of the quadrate, there is a well-defined
depression (Text-fig. 4A). This depression forms a sharp edge, slightly undercutting
the flat dorsal surface (Text-fig. 56) ; it is continued anteriorly on to the ventral
edge of the postorbital as a bevel (Text-figs. 4A, 6oB). However, Ostrom (1961,
fig. 34) concluded that the very similar depression in hadrosaurs was for the pars
superficialis, although the reptilian pars superficialis typically originates on the
medial surface of the upper temporal arch and rarely develops a prominent scar.
As Ostrorq. noted, the position and shape of the depression in hadrosaurs suggest
that it is an extension of the lower temporal fenestra and is consequently a reflection
of the superficial temporal muscle. Only a small area is involved and this would
concentrate the stresses, resulting in the prominent scar (Ostrom 1961). Insertion :
there are no well-defined insertion markings to indicate the area of insertion in
ISLE OF WIGHT, ENGLAND in
Hypsilophodon or hadrosaurs. However, it probably inserted on to the postero-
dorsal edge of the surangular and to its medial surface. The more dorsal part of
this edge near the coronoid is much thicker (Text-fig. loB), the reverse of the position
in hadrosaurs, but it lacks the well-defined and slightly concave dorsal surface present
in hadrosaurs. The partes medialis and profundus probably inserted in the same
region.
A more lateral subdivision of the superficialis, the M . levator, anguli oris, was
possibly present on the ventral border of the jugal. Ostrom (1961) noted that this
border in hadrosaurs and Iguanodon shows a pronounced ventral lobe which was
possibly for this muscle. A similar lobe is well developed in Protoceratops and was
probably for the same muscle (Haas 1955) as was the large lobe in Heterondontosaurus
(see Crompton & Charig 1962, fig. iB 'J.F.'). The anguli oris probably inserted in
front of the coronoid and on the quadratomaxillary ligament (Ostrom 1961) or
possibly on to the outer surface of the coronoid region.
Pars medialis. Origin : in modern reptiles this muscle is medial to the pars super-
ficialis but occupies a similar position. In hadrosaurs there is a well-defined area
for the pars medialis on the medial surface of the postorbital and the lateral process
of the squamosal ; it is bounded posteriorly by a well-defined ridge on the squamosal
(Ostrom 1961, fig. 36). This ridge is absent in Hypsilophodon but the area occupied
by the medialis was probably the same.
Pars profundus. Origin : in modern Sauropsida this muscle fills most of the upper
temporal fenestra. In hadrosaurs Ostrom (1961, fig. 38) located this origin chiefly
on the parietal and squamosal next to the medialis. The anterior limit is defined
by a gentle ridge running postero-dorsally across the side of the parietal. In
Hypsilophodon the anterior limit is marked by the edge of a slight depression on the
ventro-medial half of the parietal (Text-fig. 60 A). Consequently the pars profundus
probably originated from the ventro-medial part and the lateral wing of the parietal
and, in addition, from the anterior surface of the medial process of the squamosal.
M. adductor mandibulae internus
M. pseudotemporalis. Origin : in modern reptiles the M. pseudotemporalis originates
from the deep position in the anterior part of the upper temporal fenestra, passing
anterior to the trigeminal foramen. The posterior limit of this muscle is formed by
the area of the previous muscle. In Hypsilophodon the M. pseudotemporalis over-
lapped the M. externus profundus dorsally to originate from the median crest (Text-
fig. 6oA). More anteriorly a ridge sweeps laterally across the parietal on to the
postorbital ; it is continued by the dorsal edge of the postorbital. The region
delimited by this ridge (Text-fig. 56) indicates the anterior limit of the M. pseudo-
temporalis. Insertion : Ostrom (1961) deduced that this muscle must have in-
serted on to the coronoid in hadrosaurs although there is no distinct scar on that
element. In Hypsilophodon there are, in contrast, well-developed insertion markings
for the M. pseudotemporalis on the lateral, dorsal and medial surfaces of the coronoid
bone (Text-figs. 10, 12).
112 THE WEALDEN HYPSILOPHODON
M. pterygoideus. This muscle, which is not homologous with the mammalian muscle
of that name, is divided into two parts in modern reptiles and birds. In hadrosaurs
Ostrom (1961, figs. 42, 43) placed the origin of the pars dorsalis on the well-developed
maxillary shelf formed by the postero-medial part of the maxilla and by the ecto-
pterygoid. In Hypsilophodon there is no equivalent shelf region on the maxilla but
the dorso-medial surface of the ectopterygoid is similar to that of hadrosaurs. The
pars dorsalis probably originated from the concave surface ot the ectopterygoid.
Posteriorly this surface is medially directed (Text-figs. 46, 56) but more anteriorly
it is dorsally directed (Text-fig. 56) because the surface is twisted along its length.
There is no trace of the area ot insertion but it was probably on the medial surface of
the articular postero- ventral to the quadrate as in hadrosaurs (Ostrom 1961, fig. 41).
In hadrosaurs the pars ventralis probably originated from two depressions on the
ventro-medial surface ot the pterygoid (Ostrom 1961, fig. 42). In Hypsilophodon it
probably originated from a corresponding flat surface formed by the pterygoid and
ectopterygoid (Text-figs. 46, 6A, 6oD). This muscle wraps round the ventral border
of the retroarticular process to insert on the lateral surface. In Hypsilophodon there
is a slight depression on the region below the mandibular condyle in Rig2 which was
probably for this muscle. In hadrosaurs there is a well-defined depression which
corresponds in position to that of the pars dorsalis on the opposite side (Ostrom 1961,
fig. 41). The areas of origin of the pars dorsalis and ventralis are discussed below in
more detail in Section (g.)
M. adductor mandibulae posterior . In sauropsids this muscle originates in the postero-
ventral corner of the temporal region and links the quadrate with the posterior part
of the inframandibular fossa. In hadrosaurs the anterior surface of the quadrate
shows a well-developed depression, extending on to the lower third of the pterygoid
flange, which was the area of origin ol the M. adductor posterior (Ostrom 1961, fig.
46) . The area was presumably the same in Hypsilophodon though the depression is
not visible on the pterygoid flange (Text-fig. 76). The insertion in Hypsilophodon
was clearly into the deep inframandibular fossa. This tapers anteriorly (Text-fig.
I2A) and ends (apart from the Meckelian canal running forwards) level with tooth 7.
The wall formed by the dentary bears well-developed insertion markings and this
was evidently a powerful muscle.
ii) CONSTRICTOR DORSALIS GROUP
Three divisions of the constrictor dorsalis group are recognized by Lakjer (1926).
Two of these, the M. protractor pterygoidei and M. levator pterygoidei, are concerned
with movement of the dermal skull roof and palatoquadrate (maxillary segment)
relative to the braincase (occipital segment). The third division, the M. levator
bulbi, is concerned with movements of the eyelid. The first two muscles are absent
in modern akinetic skulls such as those of Crocodilia, Chelonia and Mammalia.
Ostrom (1961) failed to find any evidence of insertion areas for the levator and
protractor pterygoidei muscles in hadrosaurs but suggested that the M. levator bulbi
was present. He noted ( : 108) that ' anterior and ventral to the trigeminal foramen,
located on the laterosphenoid between the bony grooves for the profundus and
ISLE OF WIGHT, ENGLAND 113
maxillary branches of the trigeminal nerve, is situated a moderately concave, antero-
laterally facing, triangular surface which may have served as the origin site of the M.
levator bulbi'. He stated that the position of this surface on the lateral wall of the
braincase and the direction it faces, directly towards the orbit, supported this inter-
pretation. Ostrom stated that the akinetic nature of the skull ruled out the pos-
sibility that this area was for either a levator or a protractor pterygoidei and that, in
addition, no other site for the M. levator bulbi was found on any of the numerous
skulls examined.
In Hypsilophodon there is an equivalent slightly concave surface, with insertion
markings, which bears the same relationships to the profundus (V^) and maxillary
branches (V2) of the trigeminal nerve (Text-figs. 46, 60 A) but, in contrast, it is on
the prootic and basisphenoid. In hadrosaurs there are no sutures in this region so
this surface could also be on the prootic and basisphenoid. It is considered likely
that the concave surface in hadrosaurs is the same as that in Hypsilophodon.
Oelrich (1956) gave a detailed account of the anatomy of the skull of the lizard
Ctenosaura. He showed a concave surface on the prootic and basisphenoid,
immediately below the trigeminal foramen. This surface bears exactly the same
relationship to the surrounding bones and nerves as that on the same bones in
Hypsilophodon (compare Text-fig. 46 with Oelrich 1956, fig. 8). In fig. 53 Oelrich
shows a muscle which clearly originates from this surface but it is not labelled. How-
ever, a comparison with fig. 35 shows that this is the M. protractor pterygoidei.
Oelrich (1956 : 45) stated that the M. protractor pterygoidei ' forms the lateral wall
of the tympanic cavity. It is a large fan-shaped muscle arising from the lateral
surface of the anterior inferior process of the prootic, the lateral surface of the alar
process of the basisphenoid, and the posterior border of a tendon which extends from
the proximal end of the pila antotica to the cartilage covering the anterior tip of
the basipterygoid process just above the condyle'. This suggests that the surface
on the prootic and basisphenoid of Hypsilophodon could have been for the M.
protractor pterygoidei. However, the relationship of this surface to the branches of
the trigeminal nerve clearly shows that it is the same as that in hadrosaurs which,
as Ostrom (1961) suggests, may have been for the M. levator bulbi. This possible
difference may be related to differences of kinetism. The skull of Ctenosaura is
kinetic with the M. protractor pterygoidei moving the ventral part of the braincase
away from the parietal. Presumably this was the position in the kinetic ancestor
of hadrosaurs. When the skull became akinetic the M. protractor pterygoidei was
lost. In Ctenosaura (Oelrich 1956, figs. 7, 8, 35) the M. levator bulbi originates from
the pila antotica which passes anteriorly from the area of origin of the M. protractor
pterygoidei. If the situation was similar in the ancestor of hadrosaurs the M. levator
bulbi had only to shift slightly posteriorly to occupy the surface originally occupied
by the M. protractor pterygoidei. In Ctenosaura this surface faces antero-laterally
directly towards the orbit and would provide an excellent surface for the M. levator
bulbi. However, the surface in hadrosaurs may have been occupied by a M. pro-
tractor pterygoidei which formed the lateral wall of the tympanic cavity.
It is rather difficult to determine the composition of the constrictor dorsalis group
in Hypsilophodon. If the skull was metakinetic then the group must have been as
n4 THE WEALDEN H YPSILOPHODON
in Ctenosaura with the M. protractor pterygoidei on the prootic and basisphenoid
and the M. levator bulbi on the more anterior pila antotica. In this case the M.
levator pterygoidei would have originated from the parietal but there is no trace of
such an origin in Hypsilophodon. However, this is hardly surprising because this
muscle would have been only a slip and unlikely to leave any trace. If the skull of
Hypsilophodon was akinetic then the position could still have been as in Ctenosaura
with the lateral wall of the tympanic cavity formed by the M. protractor pterygoidei.
The M. levator bulbi may have originated from the area on the prootic and basi-
sphenoid previously occupied by the M. protractor pterygoidei but, as discussed in
the next section, there are certain features which indicate that the skull might have
been kinetic.
iii) CONSTRICTOR VENTRALIS GROUP
These muscles are thin sheets which link the two mandibular rami. Ostrom (1961)
figured one specimen which shows a possible area of origin of the M. mylohyoideus
but concluded that the position was indeterminable ; the same is true for Hypsilo-
phodon.
iv) M. DEPRESSOR MANDIBULAE
As in all reptiles this branchial muscle linked the retroarticular process of the man-
dible to the dorsal occipital surface of the skull. In hadrosaurs there is an insertion
area on the medial surface of the retroarticular process (Ostrom 1961) but its position
cannot be determined in Hypsilophodon. Ostrom concluded that in hadrosaurs the
depressor fibres originated from the tip of the paroccipital process, the form of which
was probably determined by the stresses imposed by this muscle. This was pre-
sumably the case in Hypsilophodon also (Text-fig. 59A).
e) Kinetism
Versluys (1910) introduced the concept of kinetism with respect to the reptilian
skull. A kinetic skull is one in which there is a movable joint between two segments
of the braincase (neurocranium and/or dermal roofing bones). Frazetta (1962)
recognized three types which are distinguished by the position of the hinge region.
In prokinesis the hinge is between the nasal and frontal bones, in mesokinesis it is
between the frontals and parietal, while in metakinesis it is between the parietal and
supraoccipital (or other bones of the occipital series) . A kinetic skull may have one
joint (monokinetic) or two (amphikinetic) . In addition there may be movement
between individual parts of the maxillary segments (dermal skull roof and palato-
quadrate) .
In Hypsilophodon the nasals are overlapped by the frontals while the lateral part
of this sutural region is overlapped by the dorsal sheet of the prefrontal (Text-figs.
56, 6B) so it is unlikely that there was any movement in this region. The suture
between the frontals and the parietal consists of a well-developed set of inter-
digitating ridges and grooves (Text-fig. 76) . At first sight it would appear that this
suture was immobile but it is comparable to the frontoparietal suture of a large
ISLE OF WIGHT, ENGLAND 115
skull of Varanus at which movement occurred (Frazetta 1962). The presence of a
good sutural system and a slight hinging action are not necessarily incompatible
because the former compensates for any weakness resulting from the latter. The
frontal of Hypsilophodon has a laterally directed spike which is enclosed by the
postorbital (Text-figs. 46, 76, 8). The postorbital probably remained fixed in
position with respect to the parietal because there is a suture between them and
because it received the head of the laterosphenoid ventrally (Text-fig. 6B). In
addition the postorbital overlaps the squamosal with which it forms the temporal
bar. As the pars superficialis, the pars medius and part of the pars profundus of the
M. adductor mandibulae externus originated on this bar it is unlikely that there was
any movement between its two parts. A slight hinging may have occurred at the
fronto-parietal suture (mesokinetic joint) with the mesokinetic axis on the line across
the f rentals joining the two laterally directed spikes. These spikes would have
allowed rotation yet kept the frontals fixed relative to the postorbital and close
to the parietal. In Varanus the lateral part of the frontal and parietal fits into
a concavity of the postorbital (Frazetta 1962, fig. la). The presence of a process
anterior and posterior to the fronto-parietal suture also ensures that the frontal
and parietal remain close together even though a hinging action is possible.
If the skull of Hypsilophodon was mesokinetic then there would have been some
other cranial movements (Text-fig. 596). The postorbital has a long overlapping
and smooth contact surface with the jugal so it is likely that a sliding action was
possible at this suture. In the palate the pterygoid contacts the articular surface
of the basipterygoid process (Text-fig. 5Q at which movement would obviously be
possible. The nature of the sutures in the palatal region shows that there was no
other plane of movement there. The palatine is firmly sutured to the maxilla as is
the ectopterygoid. The ectopterygoid bears a triangular flange of which the apex is
medially directed. This flange is recessed into the dorsal surface of the pterygoid
(Text-fig. 56) which borders it anteriorly and posteriorly. Consequently movement
of the pterygoid on the ectopterygoid was impossible, which meant that a sliding
articulation with the palatine was out of the question.
The relationship between the parietal and bones of the occipital series remains to
be considered. Posteriorly the parietal is overlapped by the squamosal, the pos-
terior process of which overlaps the distal part of the paroccipital process (Text-figs.
76, 8) . The occiput in posterior view (Text-fig. 8) appears rather solid but the medial
part of the parietal is not sutured to the underlying supraoccipital (Text-fig. 5 A).
The postero-ventral edge of the parietal and squamosal together form a convex
curve (Text-fig. 56) so the transversely orientated metakinetic axis would have been
restricted to a small part of this edge. A hinging action would have involved only
a slight movement of the squamosal away from the paroccipital process and this may
have been possible (Text-fig. 596).
No sliding could occur at the joint between the supraoccipital/prootic and the
laterosphenoid because of the curved shape of the laterosphenoid and the nature of
its suture with the prootic (Text-figs. 46, 56, 76, 9). If the skull was metakinetic
then the maximum movement would have been at the anterior end of the latero-
sphenoid. This is expanded laterally to form a well-developed head (Text-figs. 46,
n6 THE WEALDEN HYPS ILOPHODON
6B, 76) which fits into a depression in the postorbital and frontal, opening ventrally
with vertical sides. The depression becomes progressively deeper passing laterally
(Text-fig. 7B) so that contact would have been maintained if the head of the latero-
sphenoid had moved ventrally. The head tapers laterally (Text-figs. 6B, 76) and
the dorsal part of the lateral half is rounded antero-posteriorly (Text-figs. 46, 76).
The surface of the rounded part of the head and of the lateral part resembles that of
the basipterygoid and was possibly an articular surface. In lizards (Frazetta 1962),
and presumably in some individuals of Sphenodon (Ostrom 1962), the ventral part
of the braincase moves slightly antero-posteriorly relative to the parietal. In
Hypsilophodon the posterior wall of the depression in the frontal and postorbital is
quite shallow so, with a slight ventral displacement, such an antero-posterior move-
ment might have been possible. As discussed above (Section d ii) there is a surface on
the prootic and basisphenoid which was possibly the area of origin of the M. protractor
pterygoidei, one of the muscles necessary to effect the kinetic movements.
Cox (1959) noted that the vena capitis dorsalis passes through the post-temporal
fenestra in living reptiles. It is significant that the remnant of the post-temporal
fossa is totally enclosing by the paroccipital process in Hypsilophodon. In hadrosaurs
in which the skull was akinetic Langston (1960) showed that the paroccipital process
forms the ventral border to the remnant of the post-temporal fossa. In a meta-
kinetic skull with a close but movable contact between the opisthotic and the squa-
mosal, the vena capitis dorsalis, if it passed between those two bones, would have
been subjected to pressure changes. The course of this vessel through the par-
occipital process suggests that such a movement occurred because, had it not done so,
such enclosure would have been unnecessary. From the nature of the material it is
impossible to prove one way or the other but I. consider that the skull of Hypsilo-
phodon may have been mesokinetic and metakinetic (Text-fig. 596). However, I
do not know what function these movements would have served in a herbivore. It
would be helpful to know something of the selective advantages conferred by the
quite complex kinetic movements which, according to Frazetta (1962), are retained
in the herbivorous lizards Ctenosaura and Uromastix.
f) Streptostyly
A streptostylic skull is one in which the quadrate moves relative to the other
bones of the skull. This term is not interchangeable with kinetic because the two
types of movement involved can occur independently or together. The head of the
quadrate of Hypsilophodon is triangular in outline with a rounded articular surface
(Text-fig. 4A) which fitted quite closely into a socket in the squamosal (Text-fig. 6B) .
The quadrate may have been loosely connected to the quadrotojugal but the likeli-
hood of movement was minimal because, although the quadratojugal overlapped the
quadrate ventrally, dorsally the situation was reversed. The lateral surface of the
quadrate forms an angle of about 50 degrees with the pterygoid flange. Movement
of the quadrate relative to the pterygoid must have been in the plane of this flange
so the dorsal part of the quadratojugal would have restricted movement antero-
medially ; the ventral part would have restricted it postero-laterally. The quadrato-
jugal is overlapped by the jugal and, although a slight amount of sliding is
ISLE OF WIGHT, ENGLAND 117
conceivable, the parting of this contact necessary for the independent movement of
the quadrate is considered unlikely. In addition the presence of the jugal on the
lateral surface would have limited the amount of posterior movement.
In medial view the quadrates of R2477 (Text-fig. 46, PI. i, fig. 3) and Rig2 clearly
show the postero-lateral limits of the contact area with the alar process of the ptery-
goid. This is indicated by a distinct step in the level of the surface. The region
of the quadrate on which this outline is preserved is curved in cross-section so that it
is concave in medial view. This curved part is on the shaft, the posterior edge of
which is sharp and makes an angle of about no degrees with the plane of the ptery-
goid flange. The postero-lateral part of the alar process of the pterygoid would have
been curved in cross-section with a convex lateral surface. It is apparent that any
movement between the quadrate and the pterygoid must have been one of sliding.
The curved distal part of the alar process would have fitted against the concave part
of the quadrate shaft and would have limited the anterior movement of the quadrate.
In addition the curved nature of this distal part would have reduced the likelihood
of any movement of the quadrate away from the pterygoid.
I consider that the contacts with surrounding bones would have prevented any
independent movement of the quadrate. However, a slight movement of the quad-
rate with the quadrat o jugal and jugal relative to the postorbital, squamosal and
braincase may have occurred if, as was possibly the case, the skull was mesokinetic
(Text-fig. 596).
g) The antorbital fenestra
In thecodontians such as Euparkeria (Ewer 1965) and Stagonolepis (Walker 1961)
the large antorbital fenestra is bounded dorsally by the lachrymal and ventrally by
the maxilla. In Hypsilophodon the antorbital fenestra is actually represented by
the two internal antorbital fenestrae in the medial wall of the maxilla, visible in
lateral view (Text-figs. 4A, B). The lateral opening will be called the external
antorbital fenestra while the space totally enclosed by the maxilla is the antorbital
fossa (Text-figs. 6oC, D). The medial sheet of the maxilla and lachrymal is present
in Heterodontosaums and Fabrosaurus (Crompton, personal communication), both
of which are from the Upper Triassic, but the external antorbital fenestra is large
(for Heterodontosaums see Crompton & Charig 1962). In Parksosaurus (see Parks
1926, Galton in press) the lateral sheet of the maxilla is large and the external
antorbital fenestra is small. In Dysalotosaurus (see Janensch 1955) both the ex-
ternal antorbital fenestra and the lateral sheet of the maxilla are small but a large
sheet from the premaxilla encloses part of the antorbital fossa. Camptosaurus in
lateral view is similar and Gilmore (1909 : 214-215) mentioned that the lateral
foramina in the maxilla ' are received by a large, elongate cavity situated at the base
of the dorsal process between the thin inner and outer walls, and which opens
posteriorly'.
The important point is that in these lower ornithopods there is a large fossa which
opens posteriorly into the ventral part of the orbit below the eye. This cavity
represents the antorbital fenestra, which in thecodontians also opens posteriorly
n8 THE WEALDEN HYPSI LOPHODON
(Walker 1961, Ewer 1965). Consequently the obliteration of the antorbital fenestra,
at least in these lower Ornithischia, was more apparent than real because it was
merely enclosed medially and laterally to a varying extent by thin sheets of bone.
The function of the antorbital fenestra of thecodontians has been discussed by
Walker (1961) and Ewer (1965). Both agree that in the more advanced forms the
fenestra was for the origin of an anterior portion of the pterygoideus muscle. Walker
(1961) kept the insertion of this portion on the lower jaw close to the articulation so
that it effected a rapid movement of the jaw at the beginning of the bite. Ewer
(1965) placed the insertion more anteriorly on the jaw so that this portion provided
power for the initial phase of the bite.
In Hypsilophodon the only possible exit for a muscle from the antorbital fossa is
posteriorly across the floor of the orbit. This opening in R2477 is about 4 mm wide
and it is restricted dorso-laterally by the projecting edge of the jugal (Text-figs.
56, C). As noted above, the M. pterygoideus dorsalis probably originated from the
dorsal surface of the ectopterygoid. An anterior portion of this muscle may have
extended anteriorly into the antorbital fossa. This portion would have passed
across the floor of the orbit, over the edge of the ectopterygoid (Text-fig. 56) and
medial to the coronoid to insert on the lower jaw. Only a small slip or a tendon
could have followed this route and the main part of the muscle must have been in
the antorbital fossa. However, the morphology of the dorsal surface of the ecto-
pterygoid indicates that, if the M. pterygoideus dorsalis extended anywhere, it
would have passed on to the adjacent surface of the palatine. On the anterior part
of the palatine there is a slight transverse step which may indicate the limit of such
an extension (Text-figs. 56, 6oD).
When discussing the function of the antorbital fenestra it is assumed that the
muscle concerned is derived from the M. pterygoideus dorsalis, as is the pterygoideus
D of crocodiles (Lakjer 1926), but this anterior extension could have been part of
the M. pterygoideus ventralis. In Hypsilophodon this latter probably originated
from the ventral surface of the pterygoid and ectopterygoid (Text-figs. 46, 6oD).
It is possible that a portion of this muscle passed through the vacuity between the
ectopterygoid, palatine and maxilla (Text-figs. 5A, 6A) from an origin in the antor-
bital fossa (Text-fig. 6oD). In specimen R2477 this vacuity is a rather square oval,
6 mm x 4 mm. The lateral wall of the maxilla becomes progressively shallower
posteriorly and its edge more rounded. The topography of this part of the maxilla
suggests that whatever originated from the antorbital fossa may have passed postero-
ventrally through this palatal vacuity (Text-figs. 5 A, C, PI. i, fig. i, PI. 2, fig. 2).
If a cord be passed from the top of the antorbital fossa to its posterior opening,
across the maxilla and through this vacuity, it forms a gentle curve. From the
figures of the skull it would appear that a similar course would have been possible
in the thecondontians Euparkeria (Ewer 1965), Stagonolepis (Walker 1961) and
Ornithosuchus (Walker 1961).
The function of this postulated anterior portion of the pterygoideus in Hypsilo-
phodon is not certain. If the insertion of this portion was close to the articulation it
would have aided the rest of the pterygoideus in rapidly closing the jaw to effect a
cropping action of the anterior horny beaks (function the same if portion was from
ISLE OF WIGHT, ENGLAND 119
the pars dorsalis) . Such a course would give a very long muscle with a moderately
straight course. However, the much more powerful M. adductor posterior, the
moment arm of which is quite short, would have been much more effective. If the
insertion was more anterior the pull of this muscle would tend to be in the plane of
the occlusal surface of the teeth. As a result this would add to the shearing force at
these surfaces (see Section h). To be effective this insertion should have been some
way forward in the region below the coronoid but there is no evidence to show whether
or not this was the case.
The enclosure of the antorbital fenestra in lower ornithischians without its oblitera-
tion is rather interesting. These forms could be regarded as demonstrating stages
in its closure, the space enclosed having no function, but this is not very satisfactory.
In the line leading to Parksosaurus this fossa was retained from the Upper Triassic
right through to the Upper Cretaceous (Edmonton Formation) and it still retained a
posterior exit. If this fossa was functionless it is surprising that it remained for
such a long time in a region which was important in supporting the tooth row. A
slip of the pterygoideus muscle (pars ventralis and/or dorsalis) probably originated
from this space and this slip must have remained functional in these lower orni-
thopods.
h) Jaw action
Information concerning the mode of action of the jaws can be deduced from the
arrangement and wear of the teeth, the nature of the jaw articulation and the lines
of action of the musculature as reconstructed from the form of the skull. In Hypsilo-
phodon there are several features indicating that an antero-posterior movement of
the lower jaw was not possible. The inclination of the glenoid surface of the arti-
cular at about 30 degrees to the tooth row (Text-fig. loA) would have prevented any
significant retraction of the mandibles. The anterior convergence of the tooth rows
(Text-figs. 6A, loB) would have prevented any mandibular protraction. In addition
the tooth rows are slightly curved with the individual teeth forming a rather jagged
edge. It is therefore concluded that mandibular movement consisted only of a
hinge movement about the condyle of the quadrate. The occlusal surfaces in
Hypsilophodon are at an angle of about 10 degrees to the vertical for anterior teeth
or about 25 degrees for more posterior teeth. These angles are rather approximate
because the precise orientation of the maxillae is not absolutely certain. The occlusal
surfaces were certainly not vertical because in that case the lower jaw would not fit
between the maxillae.
In Hypsilophodon the maxillary and dentary teeth are thickly enamelled on one
side and are transversely curved in opposite directions (Text-fig. 61). The convex
surface bears thick enamel in both cases and, as the enamel was more resistant it
formed a sharp edge while the rest of the tooth formed an obliquely inclined occlusal
surface (Text-figs. 15, 60, 61). The sharpness of the enamelled edge is enhanced by
the presence of serrations formed by the wear of the longitudinal ridges on the
enamelled surface of the crown. In particular the apex ridge of each dentary tooth
is very large and formed a prominent spike on the cutting edge (Text-figs. I5c, i6c).
120 THE WEALDEN HYPSI LOPHODON
FIG. 61. Hypsilophodon foxii. Diagrammatic cross-section through dentition assuming
that occlusal surface of maxillary and dentary teeth equally spaced apart. Abbreviations :
de, dentine ; e, thickly enamelled surface ; os, occlusal surface.
When a force is applied across two obliquely inclined but parallel surfaces it can
be resolved into two components using a parallelogram of forces. One component,
that responsible for a crushing action, acts perpendicular to the occlusal surfaces.
The other component, that responsible for a shearing action, acts parallel to the
occlusal surface. With the angle of the occlusal surfaces at about 10-25 degrees to
the vertical it is apparent that the shear component represented the greater propor-
tion of the total force exerted across the obliquely inclined occlusal surfaces of
Hypsilophodon. In addition, the sharp enamelled edges of both teeth would have
had a cutting action.
The lateral relationship of the occlusal surfaces of the maxillary and dentary
teeth cannot be determined from the skull material. The above analysis is based
on the assumption that the lower teeth were the same distance apart transversely
as the corresponding uppers (Text-fig. 61). However, the dentary teeth were prob-
ably closer together so that an oblique movement was possible with the teeth of only
one side in opposition at a time. The amount of shift needed is quite small and,
because the articulation surface of the quadrate (Text-fig. 6A) is much wider than
that of the articular (Text-fig. loB), such a movement may have been possible.
This oblique movement would have resulted from the asymmetrical contraction of
the jaw adductor muscles. With such a movement the sharp enamelled edges would
have cut past each other and the action at the occlusal surface would have been
almost exclusively one of shear.
The jaw adductor muscles insert on to the coronoid and the adjacent bones (Text-
figs. 59, 6oD) and their force is applied between the fulcrum (the glenoid cavity) and
the resistance (food between the teeth). As a result, the lower jaw forms a third
class lever with the adductor muscles acting somewhat obliquely. When an ob-
liquely inclined muscle inserts on to a straight lever the effective force (i.e. the moment
arm) can be increased by elevating the point of application above the axis or,
alternatively, the fulcrum can be depressed below the line of the tooth row. In
both cases the force exerted by the muscle is increased without decreasing the gape
possible ; this would be decreased if the point of insertion were moved along the
ISLE OF WIGHT, ENGLAND 121
axis further away from the fulcrum. In Hypsilophodon the coronoid process is
large so that the moment arms of the M. pseudotemporalis and the M. adductors
externus, medius and profundus were lengthened (Text-fig. 59A). The glenoid
cavity is set below the level of the tooth row so that the moment arm of all the main
adductor muscles was increased.
The average line of action, together with the moment arm, is indicated for each
muscle in the reconstruction of the skull (Text-fig. 5QA). Although not absolutely
accurate this reconstruction is adequate for general conclusions regarding the relative
size of each muscle and its moment arm. The M. pseudotemporalis and the three
divisions of the M. adductor externus were the main adductors. The M. pseudo-
temporalis has the longest moment arm but it was probably not so important as the
other three muscles combined (they have a common line of action). The M. adductor
mandibulae posterior was a large muscle but it had a small moment arm. Conse-
quently it was important for the initial closing movements but then probably func-
tioned mainly to prevent disarticulation of the jaw. The M. pterygoideus dorsalis
and ventralis were probably not very large. Their extremely small moment arm
means that they probably functioned chiefly to aid the M. adductor posterior in
preventing disarticulation of the lower jaw. As discussed in Section (g) it is possible
that an anterior portion from the antorbital fenestra inserted more anteriorly on the
jaw (Text-fig. 6oD). The only muscle acting to open the jaw, the M. depressor
mandibulae, had a small moment arm. This means that the muscle had a fast
action but exerted little force. However, there was little resistance to overcome and
the weight of the lower jaw itself would have aided its own depression. It is
apparent that the main adductors had a good mechanical position and the slight
forward inclination of the quadrate helped it to resist the forces developed. The
teeth formed an efficient apparatus for dealing with plant food as they combined
cutting, shearing and crushing.
The food was obtained initially by the cropping action of the anterior horny
beaks. As Nopcsa (1905) noted, the premaxillae are rugose anteriorly, indicating
the presence of a horny beak. The pointed predentary has a fairly smooth outer
surface but the only specimen available (Text-fig, n) is from a small individual. The
predentary was probably also covered by a horny beak because this is the case in
other ornithischians (e.g. hadrosaurs, Ostrom 1961). More posteriorly the pre-
maxillary teeth presumably bit outside the predentary. In ventral view (Text-fig.
6A) there is a step between the line of the tooth row of the premaxilla and maxilla.
In addition, much of the maxilla is visible lateral to the tooth row which, as a result,
is overhung (Text-fig. 3). The dorsal view of the lower jaw (Text-fig. loB) shows a
similar situation with much of the dentary lying lateral to the tooth row. I believe
that the corner of the mouth probably did not extend much further back than the
anterior end of the maxillary tooth row. Consequently the mouth was small and
there was quite a large space lateral to the tooth rows of the maxillary and dentary
which was necessary if the animal was to chew its food (see below : 150) The
tongue would have moved the food around so that it was chewed several times while
the space lateral to the tooth rows would have received the food prior to its next
passage between the occlusal surfaces.
122 THE WEALDEN HYPSI LOPHODON
VII. ASPECTS OF POST-CRANIAL ANATOMY
a) Individual variation
There is a surprising amount of variation between the few specimens of Hypsilo-
phodon foxii represented by articulated material. Certain of these variations are
found also in Thescelosaurus neglectus (see Galton in press a). Details of variations
with age and sex are available for Protoceratops andrewsi (Brown & Schlaikjer 1940)
but, apart from this, there is very little information in the literature concerning
variation in other species of dinosaur.
The most notable variation is the presence of the additional sacral rib in the hexa-
pleural sacrum in contrast to the pentapleural type (see page 57). In Ornithischia
the number of sacral vertebrae may vary between different species of the same
genus, e.g. Camptosaums dispar with 5 and C. browni and C. depressus with 6 (Gilmore
1909) ; Iguanodon mantelli with 5 and /. bernissartensis with 6 (Boulenger 1881,
Dollo 1883). These are generally considered to be valid species. However, in the
case of Iguanodon, van Beneden (1881) regarded the variation in the sacral count as
an individual or sexual variation ; Hooley (1912) also regarded it as a sexual variation
(with /. mantelli as the female), although later (1925) he treated the two forms as
separate species. Nopcsa (1918, 1929) considered that male ornithischians were
characterized by the presence of extra sacral vertebra(e). In Camptosaurus the
sacral difference is associated with several other differences (see Gilmore 1909,
Nopcsa 1918, 1929) while in Iguanodon there are even more (see Nopcsa 1918, 1929,
Dollo 1883, Abel 1927). However, in Hypsilophodon there are only a few other
significant differences associated with that of the sacrum. In the pentapleural
specimen Ri96, when compared with the hexapleural specimens, the peduncle of
the ilium is narrower, the facets on the ilium for sacral ribs 2 to 5 are more anteriorly
placed and the sub-acetabular part of the ischium is longer. A size difference is often
used as a basis for specific separation with fossil material but there is no justification
for this because the largest sacra of each type are about the same size (length of first
three centra 75 mm in Ri93, 71 mm in R&422). The close similarity of the teeth
and post-cranial skeletons of individuals with the two sacral types clearly shows that
they are the same genus Hypsilophodon. The specific identity or separateness of the
two sacral types depends on the taxonomic significance attached to the presence of
the additional sacral rib.
In living birds the number of sacral vertebrae does riot vary within a species
(Nopcsa 1929) and this is apparently also the case in reptiles (Werner 1895). How-
ever, the sacral count can vary in man : there are usually five lumbar and five sacral
vertebrae but this count can be four and six or six and four (Brash & Jamieson 1943).
Consequently the number of sacral vertebrae (and hence ribs) can vary within a
species. In view of the position in man and the individual variation shown by R5829
I consider that the two sacral types are best regarded as individual variations of
Hypsilophodon foxii. However, even if the two types were to be regarded as sep-
arate species it would be inadvisable to give them taxonomic status because the sacral
type of the holotype of Hypsilophodon foxii is not known.
ISLE OF WIGHT, ENGLAND 123
The presence of an extra sacral rib (or vertebra) cannot be regarded as an age
variation because the smallest specimen available ^5830) already has the extra
sacral rib. The sacral difference in Hypsilophodon probably represents a sexual
dimorphism, with the hexapleural type as the male. The sacral type can be deter-
mined in only eight individuals, there are five hexapleural forms and three penta-
pleural forms. It is interesting that Nopcsa (1929) used the high ratio of Iguanodon
bernissartensis (regarded as the female) to 7. mantelli (23 : i) at Bernissart as evidence
for herding in this species (7. mantelli) .
The specimens of Hypsilophodon show quite a few other variations which were
mentioned in the descriptions of the individual elements. The differences that appear
to be correlated with the sacral difference have already been noted. Individual
variations relate to the presence of the cavity in the premaxillae ; the contacts of
the lateral sheet of the maxilla with the premaxilla and with the lachrymal and
jugal ; various features of the sacrum ; the degree of ventral curvature of the
anterior process of the ilium and the size of the medial ledge along its ventral edge ;
the opening or closure of pubic foramen in small or large individuals ; the cross-sec-
tion of the post-pubic rod ; the outline of the ventral junction between the head and
shaft of the ischium ; the degree of development of the depression at the base of the
fourth trochanter of the femur ; the form of the edges of the tibia ; and the outline
of the posterior junction between the shaft and the blade of the scapula. Variations
related to increased size probably include the ankylosis of the neural arches, ribs
and centra of the sacral vertebrae ; the presence of strong sutural ridges between the
scapula and coracoid ; the greater angularity of the edges of the scapula and cora-
coid and the greater degree of twisting of the shaft of the scapula and humerus.
b) The first sacral rib
In the reconstructions of Hypsilophodon by Hulke (1882), Marsh (1895, 1896^, b),
Swinton (1934, 19360;) and von Huene (1956) the iliac peduncle is shown square-
ended with the first sacral rib fitting on to the base of the anterior process. How-
ever, the first sacral rib actually fits against the iliac peduncle (Text-figs. 4yA, 506,
516). This is the same as in Thescelosaurus (see Gilmore 1915, Galton in press a),
Camptosaurus (see Gilmore 1909) and Dysalotosaurus (see Janensch 1955).
The peduncle region in Hypsilophodon, like that in most other Ornithischia, is
quite slender and roughly triangular in cross-section (Text-fig. 476) with the facet
for the first sacral rib facing dorso-medially. As a result of the wedge-shaped cross-
section the acetabular margin of the peduncle is horizontal yet there is a broad sutural
surface with the first sacral rib. The slender peduncle region is therefore backed
by the first sacral rib through which the thrust from the femur is transmitted to the
vertebral column. This becomes progressively more important as the vertebral
column is held more vertically. The first sacral rib is extremely thick and almost
cubical (Text-fig. 27). The ends of sacral centra i and 2 form a large contact surface
and then flare out to embrace the proximal part of the first sacral rib (Text-fig. 276).
This is also the case in Thescelosaurus, Camptosaurus, the English 'Camptosaurus'
prestwichi (see Gilmore 1909) and Dysalotosaurus. In these dinosaurs, as was
124 THE WEALDEN HYPS I LOPHODON
probably the case in all lower Ornithopoda, the first sacral rib performed a key role
in strengthening the iliac peduncle.
In Hypsilophodon the additional sacral rib in the hexapleural type of sacrum must
have acted as an anterior brace for the first sacral rib and, in addition, helped to
spread the thrust anteriorly. In R582Q this action was enhanced by the sutural
union of the new sacral rib with the transverse process of the first sacral vertebra.
It is perhaps relevant that the peduncle is more expanded transversely in forms with
a hexapleural sacrum than in the other type but more specimens are needed to
confirm this difference and, in addition, to provide more information about the
union between the neural spines. In Rigs, which has a hexapleural sacrum, the
edges of the neural spines of sacral vertebrae i and 2 are thick and closely united
by a suture (Text-figs. 25E, F, 276). Such a suture would further strengthen the
union between the two vertebrae supporting the first sacral rib. However, the
union between the neural spines is variable even in the few sacra available.
The iliac peduncle is slender and only the tip could have contacted the pubis.
Here there is a small rugose area running diagonally across the end of the peduncle
(Text-figs. 476, 5iC). This sutural surface is surprisingly small in comparison with
the corresponding surface on the pubis (Text-fig. 52 A). Anterior to the concave
acetabular region, which in life was probably covered by cartilage, there are two
distinct areas which are separated by a slight edge (Text-figs. 46A, 52A). Antero-
medially there is a slightly convex area (sa. r. i) of which the plane is inclined slightly
more medially than that of the similar but smaller outer area (il.). It would appear
that the ilium sutured with the outer area while the inner one was for the first sacral
rib. The ventral surface of this rib in Ri-95 (well preserved on left side, Text-fig.
270) forms a large flat surface against which the pubis fitted. Consequently the
pubis contacted the first sacral rib in addition to the ilium. A similar contact
between the pubis and the first sacral rib is present in Thescelosaurus (see Galton, in
press a) but, because the relevant areas of the ilium, pubis and sacrum are not
known, it is impossible to determine the position in Parksosaurus. It is probable
that the pubis articulated with the first sacral rib in Dysalotosaurus , to judge from
the figures by Janensch (1955), but this possibility is not mentioned. The acetabular
aspect of the pubis is very similar to that of Hypsilophodon but the broad anterior
articular surfaces form one rounded curve. The peduncle of the ilium is almost
identical in internal and external views but the acetabular view is not given. The
first sacral rib has the same square shape but only the lateral view is given. The
pubis of the mounted skeleton of Iguanodon atherfieldensis in the British Museum
(R5764) has a broad dorsal surface which contacts a corresponding surface on the
first sacral rib when the ilium is in articulation with both bones ; Hooley (1925) does
not mention this.
c) Limb articulation and posture
i) FORELIMB
Both scapulae were displaced in specimen Rig6 so the original position cannot be
determined. However, in several specimens of Iguanodon and hadrosaurs the scapula
ISLE OF WIGHT, ENGLAND 125
is preserved lying parallel to the vertebral column which, as Lull & Wright (1942)
noted, was probably its position in life. It is reasonable to assume that this was also
the case in Hypsilophodon (Text-fig. 62) . The ventral edge of the coracoid is rough
and bore a cartilaginous extension so there is no direct evidence concerning the angle
at which the coracoid was held. When the transverse curve of the scapula and
coracoid (Text-fig. 346) is compared with that of the anterior dorsal ribs it appears
that the coracoid probably made an angle of about 35 degrees ( ± 5 degrees) above the
horizontal.
In reconstructions of bipedal dinosaurs the humerus is usually shown held ver-
ti;ally below the glenoid. Gregory (in Osborn 1917) and Sternberg (1940, 1965)
pointed out that in this position the head of the humerus is out of the glenoid cavity.
They concluded that the humerus was held more laterally while Sternberg (1965)
thought that the ornithopod humerus was actually held horizontal. If maintaining
contact between the limits of the articular surfaces of the humerus and the glenoid
cavity was the factor limiting the range of movement, then this range was very
restricted in the transverse plane. In Hypsilophodon this range would have been
about 30 degrees : from 35 to 65 degrees to the vertical (or 90 to 120 degrees to the
lateral surface of the coracoid). However, in the crocodile the range of movement
is at least 90 degrees : from horizontal and lateral to vertically below the body in the
high walk and the gallop (Cott 1961) . It would be surprising if the range of movement
was less than this in Hypsilophodon. It should be noted that the articular surface
of the humerus is formed by all of the proximal end, not just the convex surface of
the dorso-laterally directed 'head' (see Text-fig. 38). Consequently this 'head' can
be completely out of the glenoid (i.e. visible in lateral view) but the more medial
part of the articular surface is still in the glenoid. Although the humerus could
have been held much more laterally than shown in most reconstructions the vertical
pose was probably quite normal. The anterior limit of movement of the humerus
can be determined because the anterior edge of the head comes up against the
scapula. The edge of the glenoid in this region is reduced, forming a depression
(Text-fig. 35A) into which fitted the humerus. The anterior limit is such that the
delto-pectoral crest is approximately perpendicular to the adjacent lateral surface
of the scapula.
The elbow joint, radius and ulna are similar to those of other dinosaurs. The
articulations at the wrist cannot be determined because this region is badly preserved.
The manus was undoubtedly capable of grasping. The phalanges of the first three
digits are well formed (Text-fig. 41) and the third digit, with four phalanges, must
have been capable of a large amount of flexion. Distally the fifth metacarpal has a
definite condylar end with a well-defined articular surface which undoubtedly carried
at least one phalanx. This metacarpal is certainly small but this does not neces-
sarily mean that digit V was reduced. Metacarpal V of Iguanodon, relative to the
other metacarpals, is proportionally only slightly larger than that of Hypsilophodon
yet it bears four well-developed phalanges - the longest set in the hand (see Hooley
1925). In hadrosaurs the fifth metacarpal is about a third of the length of meta-
carpal III but it still bears three small phalanges (see Park.'; 1920 for Kritosaurus,
Lull & Wright 1942 for Anatosaurus] .
126 THE WEALDEN HYPSI LOPHODON
Proximally the lateral corner of metacarpal IV (Text-fig. 416) closely resembles
the medial corner of metacarpal I and, in the absence of metacarpal V, it would be
assumed that digit V was completely reduced. This indicates that metacarpal V
was not held alongside metacarpal IV but set at an angle, though this has probably
been somewhat exaggerated as preserved in this specimen. The proximal end of
metacarpal V, which articulated with the ulna, is slightly concave with a relatively
extensive articular surface dorsally and ventrally. This indicates that quite a wide
range of movements were possible, including a certain degree of ventral rotation.
With metacarpal V in the same plane as the other metacarpals (Text-fig. 41) its
phalanges would face ventro-medially because, as a result of the twisted shaft, the
distal articular surface is set at an angle of about 135 degrees to the horizontal (a line
through the transverse plane of the carpus). In this feature it is comparable to the
human first metacarpal, the distal end of which makes a similar angle (45 degrees in
this case). The condylar regions of metacarpals II to V are horizontal in man.
However, as preserved it appears that in Hypsilophodon those of metacarpals II
and III are set at an angle of 45 degrees to the horizontal so that these digits face
ventro-laterally (Text-fig. 416). With the fifth digit facing ventro-medially its
joint surfaces are perpendicular to those of the second and third digits. This reduced
the amount of ventral rotation necessary before the fifth digit was truly opposable.
However, more material is needed to confirm the nature of the distal articular sur-
faces of metacarpals II, III and V.
ii) HINDLIMB
The femur was certainly held beneath the body. With its head set on a well-
developed neck perpendicular to the shaft, no other pose was possible. The distal
surface is somewhat obliquely inclined in posterior view (Text-fig. 54D) . However,
the corresponding surface of the tibia slopes the other way (Text-fig. 566) so that the
tibia moved more or less antero-posteriorly on the femur. The range of movement
of the tibia cannot be determined because this depended on the restraining action of
the knee capsule ligaments. The head of the fibula articulated with the groove on
the lateral surface of the outer condyle of the femur when the knee was fully flexed.
In dinosaurs the joint between the tibia/fibula and the proximal tarsals was
rendered immobile in various ways to form a mesotarsal joint. In ornithischians
the joint is between the proximal and the distal tarsals, with both the astragalus and
the calcaneum firmly attached to the tibia/fibula. In Hypsilophodon the distal
end of the tibia is broad and backs the calcaneum as well as the fibula. The astra-
galus wraps round the inner malleolus with an anterior ascending process which was
attached by ligaments to the adjacent part of the tibia (strong insertion markings
here, see Text-fig. 56G). With a digitigrade pose the metatarsals, because they meet
the tibia at an obtuse angle, would tend to rotate the astragalus anteriorly but the
anterior process of the astragalus prevented this. The proximal tarsals, although
firmly attached to the tibia and fibula, were not fused to them because they have
shifted in most specimens. However, apart from small specimens (e.g. 1^5830) it
appears that the astragalus and calcaneum were ankylosed together because no
division is visible between them in larger specimens.
ISLE OF WIGHT, ENGLAND 127
The functional ankle joint was between the proximal and distal tarsals, which
were firmly attached to the tibia/fibula and to the metatarsus respectively. The
range of possible movement at this joint is easily determined because the markedly
convex articular surface of the calcaneum must have retained contact with the second
distal tarsal. This gives a minimum angle of 60 degrees between the tibia and the
metatarsus and a maximum of 180 degrees.
There was probably no movement between the distal tarsals and the metatarsals.
Distal tarsal I fits across the joint between metatarsals II and III, engaging a small
boss on metatarsal II, and there are well-developed radial striations indicating a
strong ligamentous connection. The corresponding surfaces of distal tarsals I
and II are of similar form so that they made a good fit. There were probably car-
tilaginous elements for the rest of metatarsals I and II which, together with the
proximal and distal tarsals, were surrounded by a strong joint capsule. Metatarsals
I to IV were closely applied to each other with broad contact surfaces so it is very
unlikely that there was any movement between them and the metatarsus was
therefore rigid.
In the reconstructions of the foot by Hulke (1882, pi. 82) and Abel (1912, fig. 293)
the fifth metatarsal, relative to the other metatarsals, is shown much too long ;
but in Marsh (1895, fig. 9), Heilmann (1926, fig. 115) and Romer (1966, fig. 241) it is
correctly drawn. In all these reconstructions the fifth metatarsal is shown lateral
to metatarsal IV and also, except in those by Hulke and Romer, closely applied to
the lateral edge of metatarsal IV. Proximally this edge is moderately rounded
(Text-fig. 57H) but it soon becomes extremely sharp-edged so it is unlikely that
metatarsal V occupied this position. The second distal tarsal is wedge-shaped in
lateral view (Text-fig. 5yM) with a broad and rounded ventral articular surface
(Text-fig. 57J) for metatarsal V. In S.M. 4129 metatarsal V is preserved across the
ventral surfaces of metatarsals IV and III with its proximal end in contact with
distal tarsal 2. Metatarsal V is on the ventral surface of the metatarsus in all the
other specimens where it is preserved (Ri93, RigG, R2Oo) and this was probably its
natural position. In Thescelosaurus metatarsal V is ventral to metatarsal IV (Gil-
more 1915, fig. 16) while Parks (1926 : 37) noted that in Parksosaurus metatarsal V
is 'known only by a small bone under the palmar surface of the left foot'.
iii) QUADRUPEDAL OR BIPEDAL POSE AND THE POSTURE OF THE VERTEBRAL COLUMN
In the reconstructions by Hulke (1882) and Heilmann (1916) Hypsilophodon is
shown in a quadrupedal pose while Marsh (1895), Abel (1922, 1925), von Huene
(1956), Swinton (1962) and Colbert (1965) show it as a biped. In the reconstructions
by Smit (in Hutchinson 1894) and Swinton (1934, 19360, 1954) both poses are
given. Heilmann (1916, 1926) noted that Hypsilophodon was not normally bipedal
because the structure of its pelvic girdle was similar to that of the completely quadru-
pedal Stegosaurus. Consequently the form and proportions of the limbs must be
considered to see whether or not Hypsilophodon could have run quadrupedally.
The manus is very small, when compared with the pes from the same individual
(Text-figs. 41, 58), and it is adapted for grasping rather than for locomotion. The
I28 THE WEALDEN H YPSILOPHODON
long bones of the forelimb are smaller and much more slender than those of the
hindlimb. Consequently it is unlikely that the forelimb supported the body while
the animal was running. Hypsilophodon has a forelimb 58-6 per cent of the length
of the hindlimb ; if the metacarpals and metatarsals are included, the ratio is 52-5
per cent. The hindlimb would have greatly outstepped the forelimb and this would
have been especially significant if the animal remained on all fours while trying to
run. In order for the hindlimbs to make their full stride while the animal is quadru-
pedal the acetabulum must have been much higher than the glenoid cavity. As a
result the dorsal vertebral series would have to be obliquely inclined and rise upwards
to the pelvis. The presence in RiQ6 of an uninterrupted series of ossified tendons
from the fifth dorsal vertebra to the end of the sacrum indicates that this part of the
column was relatively rigid with only a limited amount of bending in the sagittal
plane. The sacral series would also be obliquely inclined and the column would
curve downwards again only at the anterior part of the tail. These points are shown
in Heilmann's reconstructions (1916, fig. 76) and the dorsal and sacral series are at
an angle of 25 degrees to a line passing through the manus and pes. The knee is
still quite strongly flexed and for a full stride this angle would be even larger. The
overstepping effect and the resulting pose make it impossible for Hypsilophodon to
have run quadrupedally.
To run efficiently it is important that the limb be positioned under the body be-
cause this lengthens the stride, improves the leverage exerted by each segment of the
limb during propulsion and reduces the amount of lateral swinging of the limb during
recovery. The lengthening of the distal parts of the hindlimb is an adaptation for
fast running with a fore and aft movement of the limb but the distal parts of the
forelimb are not elongated (Table V). In fast running quadrupedal ungulates and
carnivores the fore and hindlimbs are modified to a comparable degree (see ratios in
Gregory 1912). The restriction of cursorial adaptations to the hindlimbs in Hypsilo-
phodon clearly shows that the animal was bipedal.
To move bipedally, the hindlimb should be long relative to the trunk (Ewer 1965).
The trunk length can be taken as the distance between the glenoid cavity and the
acetabulum. If the leg length be taken as femur and tibia, then the ratio leg length :
trunk length is 1-26 which is higher than in modern lizards which are facultatively
bipedal (see Ewer 1965, fig. 16 - Basiliscus - 1-05). However, because Hypsilo-
phodon was digitigrade, the third metatarsal should also be included in the leg
length, increasing the ratio to 1-59. The trunk is clearly short enough, relative to
the hindlimb, for bipedal locomotion. The tail, which is an important balancing
organ for facultatively bipedal lizards (Snyder 1962), is sufficiently long in Hypsilo-
phodon for this purpose. In addition the rigidity of the posterior two-thirds of the
tail, which is ensheathed in ossified tendons, would increase its efficiency as a
balancing organ. The small size of the head and forelimbs made balancing easier
because it reduced the weight anteriorly. It is therefore apparent that Hypsilo-
phodon ran bipedally and could not have done so quadrupedally.
As discussed elsewhere in detail (Galton 1970) I consider that the sacrum of
hadrosaurs and iguanodontids was held horizontally while running. This is the pose
in living bipeds apart from primates and facultatively bipedal lizards. It was
ISLE OF WIGHT, ENGLAND
129
»v-; W^rBa:.-.7--.>::-'- •
— — "S»CS^,,
FIG. 62. Hypsilophodonfoxii. Skeletal and flesh reconstruction showing bodily proportions
of an animal about 1-36 m., or 4.5 ft. long (based mainly on R 196, see p. 19). Flesh
reconstruction kindly provided by Mr R. T. Bakker of Harvard University.
probably the case in Hypsilophodon but the anatomical evidence is not nearly so con-
clusive as it is for hadrosaurs. Ossified tendons are well developed in Hypsilophodon
but there is no rhomboidal pattern comparable to that in hadrosaurs. However,
this would not seem necessary because Hypsilophodon is quite small (specimens
known up to 2-28 m). Indeed, the presence of any ossified tendons in an animal of
this size is surprising. The tendons of the dorsal series, arranged in parallel rows,
would have been quite adequate to prevent a ventral sagging of the column in a
horizontal pose and this was probably their function.
130 THE WEALDEN H YPSILOPHODON
The pubic peduncle of the ilium (Text-figs. 46 A, 48, 49) is slender but this region
was not weak because it is backed by the massive first sacral rib (see Section b),
through which the thrust of the femur would have been transmitted to the vertebral
column. The vertebral column could have been swung to 40 degrees above the
horizontal, the standard 'upright pose', without any danger. However, with a
horizontal vertebral column the femur would still bear against the strongest part of
the ilium. The central part of the acetabular margin is the thickest and it has the
maximum height of ilium above it. In addition the thrust from the femur would
be distributed much more evenly through the sacral ribs and would be perpendicular
to the vertebral column.
Hypsilophodon was undoubtedly bipedal except when resting on the ground. In
slow walking the vertebral column was probably held at about 30 degrees to the
horizontal. In this ' upright ' pose the animal was in the most advantageous position
for catching sight of predators and it could reach foliage at a higher level than if it
was quadrupedal or horizontal. However, when running it would seem likely that
the vertebral column was held more or less horizontally (Text-fig. 62). This pose,
which is the most effective for fast running, is only possible if the animal is completely
adapted for bipedal locomotion and has a tail that can provide the necessary counter-
balance.
VIII. WAS HYPSILOPHODON ARBOREAL?
a) Historical survey
Since Hulke (1882 : 1055) concluded that ' Hypsilophodon was adapted to climbing
upon rocks and trees' there has been a considerable amount of discussion on this
matter. Abel (1912) argued from the structure of the hind-foot that Hypsilophodon
was arboreal and that in this it retained the original habitat of the ancestor of all
the dinosaurs. In his reconstruction the first toe is shown as being opposable to the
remaining three toes, which are shown curving strongly backwards (Text-fig. 63).
Abel said that this curvature was natural, rather than due to a post-mortem con-
traction of the tendons, because the position and attitudes of the articular surfaces
would permit no other reconstruction. He considered that this was not a raptorial
foot because the structure of the teeth clearly showed that Hypsilophodon was
herbivorous. Abel concluded that the opposability of the hallux in combination
with the strong flexural capabilities of the remaining toes clearly proved that
Hypsilophodon was arboreal. He suggested that the foot was used to grip round
branches as in an arboreal bird.
Heilmann (1916) agreed that Hypsilophodon lived in trees but regarded this as a
secondary adaptation from a ground-living ancestor. He believed that, because
the first metatarsal of Hypsilophodon was shortened exactly as in the ground-living
dinosaurs, the ancestor of Hypsilophodon must also have been terrestrial. A result
of this shortening of the first metatarsal is that the first toe arises at a higher level
on the foot than the other three toes. Heilmann thought that this would have pre-
vented Hypsilophodon from gripping like an arboreal bird in which all the toes arise
ISLE OF WIGHT, ENGLAND 131
FIG. 63. Hypsilophodon foxii. Pes as figured by Abel, based on Rig6 and figures in
Hulke (1873, 1882). After Abel (1912, fig. 283).
at the same level. He felt that the foot was more reminiscent of that of a monkey
and, as a result, this secondary adaptation to an arboreal mode of life was analogous
to that of the tree kangaroo Dendrolagus.
Abel (1925) admitted the correctness of Heilmann's conclusion that Hypsilophodon
was secondarily arboreal. He opined that the first metatarsal was not further
reduced because it was probably used in climbing and extended the analogy with
Dendrolagus as a basis for reconstructing the pose of Hypsilophodon. He thought
that the sharp and strongly arched claws of the hind-foot of Hypsilophodon would
have rendered movement on the ground difficult. He referred to his own reconstruc-
tion of the fore-arm (1911) and pointed out that in Hypsilophodon, in contrast to the
other dinosaurs, the radius was distinctly bowed. He cited Carlsson (1914), who had
shown that Dendrolagus differed in the same manner from the large ground kangaroo
Macropus. Carlsson regarded this enlargement of the space between the fore-arms
in Dendrolagus as an adaptation to an arboreal mode of life.
Heilmann (1926) disagreed with Abel's conclusion that Hypsilophodon was ar-
boreal (and, presumably, with his own similar conclusion of 1916). He pointed out
that the cursorial Procompsognathus triassicus has ungual phalanges which are even
more markedly bent than those of Hypsilophodon. Although Abel's reconstruction
of the foot was based mainly on the figures of Hulke, Heilmann noted that it did not
look like these ; furthermore, the individual elements did not agree with the measure-
ments given by Hulke. In addition Heilmann thought that in Abel's reconstruction
the first toe would collide with the second metatarsal. He again pointed out that
the proximal position of the hallux made it impossible for Hypsilophodon to grasp in
a fashion similar to that of an arboreal bird. In order to grip a branch the first
metatarsal of Hypsilophodon must have been movable, as is the first metacarpal in the
human hand. Heilmann showed that this was not the case by quoting Hulke
(1882 : 1053), who wrote that the proximal ends of the metatarsals 'are in closest
mutual apposition'. Heilmann considered that the foot was not specialized for
climbing. He reconstructed the foot using Hulke's figures, and the toes are shown
9*
132 THE WEALDEN HYPSI LOPHODON
straight with no opposability of the hallux. He also thought that the hand was not
specialized for climbing. Heilmann reiterated his belief that Hypsilophodon was
quadrupedal (see above, page 127) but did not explain why this would have pre-
vented Hypsilophodon from being arboreal, especially as his reconstruction (1916)
showed Hypsilophodon climbing with a quadrupedal pose. Lastly, he pointed out
that the presence of dermal armour was unexpected if Hypsilophodon was a tree
climber, because arboreal animals are not usually so equipped.
Abel (1927) noted Heilmann's conclusion that Hypsilophodon was not arboreal but
did not answer any of the points raised. He admitted that the tail of Hypsilophodon
could not have been prehensile because of the ossified tendons (an objection that was
not raised by Heilmann) but noted that a non-prehensile tail occurs in some tree-
geckos. Abel also took further examples from Carlsson (1914) to show that the
enlargement of the space between the fore-arms is an arboreal adaptation.
Swinton (1936) suggested that the arm in Hypsilophodon had a greater range of
brachial movement than in Thescelosaurus, Camptosaurus or Iguanodon. The
reasons given were the more medial position of the articular head of the humerus,
the more proximal position of the delto-pectoral* crest and the fact that the
humerus is longer than the scapula. Swinton admitted that the hand was not
specialized for climbing. However, he pointed out that the three relatively elongated
middle digits and the long, thin, pointed and curved unguals show that the hand was
suitable for grasping, provided that no great weight was to be supported. Concern-
ing the foot he noted that, even in Heilmann's reconstruction (1926), the first meta-
tarsal is shown diverging distally from the rest. He considered that the first digit
was opposable even though it was more proximally placed on the metatarsus. He
pointed out that in the human hand some opposable action of the thumb is still
possible even when the first metacarpal is forcibly kept against the second. How-
ever, Swinton (1936) admitted that the amount of opposability was probably exag-
gerated by Abel who argued on the basis of an unnaturally retracted foot.
Though some elongation of the hindlimb has taken place, the tibia being longer
than the femur, Swinton (1936) pointed out that truly cursorial animals have an
elongate metatarsus - a modification lacking in Hypsilophodon. Swinton also
noted (1936 : 576) that in 'Hypsilophodon (and even more so in Thescelosaurus} the
fourth trochanter extends at least to the distal half of the bone, and this suggests
that though the muscles may have been powerful their mere presence in this position
hampered femoral movement to some extent'. From the structure of the hindlimb
he concluded that, although bipedal, Hypsilophodon could not run fast but that the
musculature was sufficient for climbing and balancing. In addition he noted that
the tail must have been a rigid structure because of the presence of ossified tendons
and that it must have helped in balancing. Swinton (1934) noted that dermal
armour was shown in Heilmann's reconstruction (1916) but that, as it was only
light, this was not a serious objection to Hypsilophodon 's being arboreal. Later
(19360) he pointed out that this armour was insufficient to protect Hypsilophodon
* Swinton (1936 : 575) actually cited 'the more proximally placed radial crest* but no such structure
was mentioned in his description ( : 563-564) and, from the context, it is apparent that he meant the
delto-pectoral crest. He mentioned ( : 564) that the deltoid crest was more proximally placed than in
the other genera, 'a point which will be considered further later'.
ISLE OF WIGHT, ENGLAND 133
from contemporary carnivores and that it was probably not fleet enough to escape
by running. He suggested that, in times of danger, Hypsilophodon climbed up into
the trees where, in addition, it obtained its food.
More recently, S win ton (1962 : 24) wrote that 'it has been thought that the
lengths of the fingers and toes of Hypsilophodon indicate that it could climb trees ;
but this is probably a wrong assumption, though the animal could no doubt run up
sloping trunks'. However, the accompanying reconstruction (pi. 9) showed
Hypsilophodon well up a tree. Romer (1956 : 414) noted that in 'Hypsilophodon,
digit I diverges from its neighbours, as in Thescelosaurus, but is relatively long, with
digital articulations suggesting a clutching power and hence habits possibly somewhat
arboreal in nature for ancestral ornithischians'. More recently (1966 : 158) he noted
that ' some structural features of Hypsilophodon suggest arboreal habits comparable
to those of the tree-kangaroo of Australia'. These features, which have been
mentioned above, can be summarized according to the region concerned as follows :
b) Summary of the purported anatomical evidence that Hypsilophodon was arboreal
i) Grasping capabilities of the pes :
A) Strong flexural ability of the long toes and the long, thin, pointed and
curved unguals.
B) Opposability of the hallux.
ii) Grasping capabilities of the manus :
A) Length of the middle three digits.
B) Long, thin, pointed and curved unguals.
iii) Wider range of brachial movements possible :
A) Humerus longer than scapula.
B) More proximal position of the deltopectoral crest of the humerus.
C) Medial position of the articular head of the humerus.
iv) Nature of fore-arm with a marked bowing of the radius which, by analogy
with Dendrolagus, is an arboreal adaptation, and which is not found in other
dinosaurs.
v) Rigid tail an aid to balancing,
vi) Dermal armour only light and therefore inadequate as a protection from
ground-living predators,
vii) Limited running capabilities on the ground resulting from the structure of the
hindlimb :
A) Sharp and strongly arched claws hampered movements.
B) Metatarsus not elongated as in truly cursorial forms.
C) The low position of the insertion of leg muscles on the fourth trochanter
of the femur.
c) Discussion of this evidence
i) GRASPING CAPABILITIES OF THE PES
Abel (1912), when discussing his reconstruction of the foot (see Text-fig. 63), con-
sidered that the pose shown was natural because the nature of the articular surfaces
134 THE WEALDEN HYPS ILOPHODON
permitted no other reconstruction. If this is correct then Hypsilophodon must
have found it rather difficult to change its grip ! However, the nature of the flexural
abilities of the toes as determined by the articular surfaces, together with the lengths
of the phalanges and the nature of the unguals, is no different in Hypsilophodon from
what it is in the hypsilophodontids Thescelosaurus (see Gilmore 1915), Parksosaurus
(see Parks 1926), Dysalotosaurus (see Janensch 1955, 1961) and the psittacosaurid
Psittacosaurus (Colbert 1962, fig. 29). Outside the Ornithischia the digits of the feet
are also very similar in most pseudosuchians (Hesperosuchus, see Colbert 1952),
coelurosaurs (Coelophysis, Colbert 1962, fig. 8) and prosauropods (see comparison of
feet of Hypsilophodon and Anchisaurus in Galton, 19700, Plateosaums in von Huene
1926). Even in the relatively short phalanges of larger dinosaurs the articular sur-
faces are still very similar ; the unguals of Camptosaurus (see Gilmore 1909) and
Iguanodon (see Hooley 1925) are moderately curved. However, the unguals of
ornithomimids, which are regarded as cursorial dinosaurs par excellence (Osborn
1917, Colbert 1962, Romer 1956, 1966) are even more pointed, longer and thinner
than those of Hypsilophodon. It is apparent that digits II to IV of the foot of
Hypsilophodon closely resemble those of many other dinosaurs.
Only in specimen Ri96 are the feet well preserved with articulated phalanges and
Abel (1912) clearly based his reconstruction on this specimen. As drawn (Text-fig.
63) metatarsal V is too long and the length and proportions of most of the phalanges
are incorrect. However, the first metatarsal is shown closely applied to the side of
metatarsal II and its first phalanx is quite accurately drawn from the right foot.
An examination of the complete first digit of the left foot (PI. 2, fig. 3) shows that the
curved ungual should point ventrally. The correctness of this articulation is con-
firmed by comparing the distal articular end of the first phalanx with the correspond-
ing region on digits II to IV (see Text-fig. 58). Consequently Abel (1912) in his
reconstruction rotated the first ungual through 180 degrees so that it pointed dor-
sally instead of ventrally.
In Ri96 the first metatarsal is closely applied along its whole length to metatarsal
II as drawn by Abel (1912) and Heilmann (1926). Swinton (1936) stated that
Heilmann (1926 : 162) showed the end of metatarsal I diverging distally. However,
it would appear that Swinton had looked at figure 115 (4), that of Anomoepus (foot
reconstructed from footprints from the Upper Triassic of the Connecticut Valley, in
which metatarsal I indeed diverges), rather than figure 115 (3) of Hypsilophodon, in
which metatarsal I is shown closely applied to metatarsal II. Swinton noted that in
the human hand some opposable action of the thumb is still possible even when the
first metacarpal is kept closely approximated to the second. However, metacarpal I
cannot be closely approximated to metacarpal II because there are muscles that get
in the way. In addition, this opposability of the thumb is rather ineffective and is
merely a result of the angle of the distal articular condyle of metacarpal I. With
the wrist held horizontally this angle is about 45 degrees to the horizontal so that the
phalanges of digit I can be moved towards those of the adjacent digit (i.e. ventro-
laterally). In Hypsilophodon the plane of the condyle of metatarsal I is approxi-
mately horizontal so that the phalanges of digit I can move only ventrally or even
slightly ventro-medially. The fifth digit of the human hand would provide a better
ISLE OF WIGHT, ENGLAND 135
analogy. In both cases no amount of distal divergence will make the digit opposable,
only a considerable amount of ventral rotation of metacarpal V (or metatarsal I).
The first metatarsal of Hypsilophodon has a greatly compressed proximal portion
which wraps round on to the dorso-lateral surface of the second metatarsal (see
description and Text-fig. 58). In addition, there is practically no proximal articular
surface. There is no isolated first metatarsal but it would closely resemble that of
Parksosaurus (Parks 1926, figs. 15, 16). In both Hypsilophodon and Parksosaurus
the form of the first metatarsal shows that any lateral movement away from the
second metatarsal was impossible and, as a result, ventral rotation was out of the
question. Consequently the most important argument for regarding Hypsilophodon
as a tree-climber, the opposability of the hallux, is based on misinterpretations of
the material.
ii) GRASPING CAPABILITIES OF THE MANUS
The ungual phalanges of the manus resemble those of the pes but Swinton (1936 : 676)
exaggerated slightly in describing them as long and thin. He also mentioned the
'comparatively elongated three middle digits' while, as can be seen in Text-fig. 41,
the fourth digit is in fact quite short. Although Abel, Heilmann and Swinton argued
that the hallux of Hypsilophodon was opposable, they did not discuss the possibility
that the fifth digit of the hand was opposable as may have been the case (see page
126).
The hand of Hypsilophodon could probably grasp objects very well, provided that
they were small. The manus is much smaller than the pes (Text-figs. 41, 58, both
from specimen Ri96) with metacarpal III, the longest in the hand, being shorter
than the rudimentary metatarsal V. The small size of the manus would have
restricted its usefulness as an aid in climbing, but a grasping hand is not confined to
arboreal forms. The fifth digit of Iguanodon bears phalanges (more than any other
digit) and metacarpal V, which has a concave proximal surface, is set at quite an
angle to metacarpal IV (Hooley 1925). The fifth digit of hadrosaurs is similar
(Parks 1920, Lull & Wright 1942). Consequently the fifth digit, which was certainly
adapted for grasping, may have been opposable, even though these ornithopods
(length 6-9 m) were much too large to climb trees. The coelurosaurs Ornitholestes
and Struthiomimus are supposed to have had an opposable first digit (Osborn 1917) ;
and the hand of the coelurosaur Coelophysis, with its long second and third digits,
was probably also a good grasping organ (Colbert 1962). The coelurosaurs are
generally regarded as cursorial forms (Colbert 1962, Romer 1966).
iii) WIDER RANGE OF BRACHIAL MOVEMENTS POSSIBLE
Swinton (1936) believed that the humerus of Hypsilophodon was longer than the
scapula. However, he based this view on specimen R5829, in which both scapulae
are unnaturally shortened because of the loss of their dorsal ends. In R5830, Rig6
and Ri92 the humerus is about the same length as the scapula (see Table II). Swin-
ton also pointed out that the delto-pectoral crest was rather proximal in position in
Hypsilophodon. However, its position in Dysalotosaurus (see Janensch 1955) and
136 THE WEALDEN H YPSILOPHODON
Iguanodon atherfieldensis (see Hooley 1925) is almost identical. Lastly, Swinton
thought that the head of the humerus was rather medial in position. However,
differences in the position of the head in Hypsilophodon, Thescelosaurus (Sternberg
1940, fig. T_4b, Galton, in press a), Camptosaurus (Gilmore 1909, fig. 26) and Iguanodon
(Hooley 1925, fig. 7 - IV) are minimal and lack any real significance. It is therefore
concluded that the range of brachial movements was not greater developed in
Hypsilophodon .
iv) LARGE FORE-ARM SPACE
The radius and ulna of Hypsilophodon are slender but the degree of development of
the fore-arm space is comparable to that of Thescelosaurus, Dysalotosaurus and Camp-
tosaurus nanus ; the radius and ulna are very similar in form in the first two genera.
The fore-arm space of Iguanodon atherfieldensis is also quite well developed. This
space is therefore not uniquely large in Hypsilophodon, and it is not true that
Hypsilophodon differs from all other dinosaurs in the same way that the arboreal
Dendrolagus differs from ground-living kangaroos.
V) RIGID TAIL AS A BALANCING ORGAN
The ensheathing tendons must have made the posterior two-thirds of the tail rather
rigid. They would have enhanced the effect of the vertical articular surfaces of the
pre- and post-zygapophyses of the caudal vertebrae from about the tenth vertebra
onwards. The attitude of these facets must have restricted movement laterally
while the ossified tendons would have also restricted it dorso-ventrally. The base of
the tail was much more flexible because the absence of tendons in this region is
probably natural and the articular planes of the zygapophyses are at about 45
degrees to the vertical. However, the distal part of the tail is also ensheathed in
ossified tendons in the other hypsilophodontids in which this region is well preserved,
namely Parksosaurus and Thescelosaurus. The tail is ensheathed in several dino-
saurs, including two from the Lower Cretaceous of Montana - an ornithopod
(Ostrom, personal communication) and a theropod (Deinonychus, Ostrom 1969).
Hypsilophodon is thus not unique in having a rigid tail, which would have been useful
while running on the ground. The rigidity would have increased the efficiency of the
tail as a dynamic stabilizer when the animal rapidly changed its direction (see dis-
cussion for Deinonychus in Ostrom 1969 : 68).
vi) DERMAL ARMOUR
Hypsilophodon is the only ornithopod in which any trace of armour has been found ;
other ornithopods were even less well protected against predators.
Vii) LIMITED RUNNING CAPABILITIES
The ungual phalanges of Hypsilophodon do not differ from those of most other
dinosaurs. In order to discuss the proportions of the hindlimb of Hypsilophodon the
ISLE OF WIGHT, ENGLAND 137
ratios for other Ornithopoda are given in Table V. Those for certain Saurischia are
also given, together with those for perissodactyls and artiodactyls considered by
Gregory (1912) as cursorial.
The ratio of tibia : femur in Hypsilophodon is, together with that of its closest
relative Parksosaurus, higher than in any other post-Triassic ornithopod. Indeed
the tibia is longer than the femur in only a few ornithischians. This ratio is higher
only in the saurischian Struthiomimus and in a few of the cursorial perissodactyls
and artiodactyls. The ratio of the third metatarsal : femur is larger in Hypsilo-
phodon than it is in any other ornithischian. However, it is low in comparison with
Struthiomimus and Coelophysis and, amongst the cursorial ungulates, the ratio is
lower only in Eohippus. The ratio of the combined length of the tibia and third
metatarsal : femur indicates the degree of elongation of the lower segment of the leg.
This ratio in Hypsilophodon (at 1-78 or 1-73) is higher than in any other post-Triassic
ornithischian while in the saurischians it is higher only in Coelophysis (1-67 or 1-86)
and Struthiomimus (1-90 or 1-99). However, coelurosaurs and more especially the
ornithomimids are generally regarded as the dinosaurs most highly adapted for fast
running (Osborn 1917, Colbert 1962, Romer 1956, 1966). This last ratio shows that
amongst the Ornithischia Hypsilophodon was the best adapted for fast running. It
falls in the middle range of the cursorial species listed by Gregory (1912) and is
better adapted than Eohippus, Mesohippus, the race-horse and Tragulus napu.
The ratio of X : femur, where X is the minimum length between the neck of the
femur and the distal surface of the fourth trochanter (Text-fig, if), is certainly lower
in most Theropoda than it is in Hypsilophodon ; the fourth trochanter is closer to
the head even in Gorgosaurus. With a low value for this ratio the caudifemoralis
longus muscle has a smaller moment arm and a faster action. This is an adaptation
that is important in cursorial animals (Gregory 1912) and, although the fourth tro-
chanter is relatively low in Hypsilophodon, it is even lower in other ornithischians
that were less well adapted for fast running.
It is concluded that Hypsilophodon was not specifically specialized for an arboreal
mode of life but, on the contrary, was cursorial. Individuals may occasionally have
gone up into the trees but this would have occurred no more frequently than in any
other small (up to 2-28 m long) and active dinosaur (see below : 149).
IX. GENERALIZED FEATURES OF HYPSILOPHODON
Hypsilophodon has been correctly regarded as a very primitive ornithopod and
the more noteworthy features will be considered briefly with comments on the
position in other ornithopods. Unfortunately the number of genera with which
comparisons can be made is necessarily limited by inadequacies in the fossil record
or in the published accounts. The relationships of Hypsilophodon are summarized
below (: 150).
The snout is short, the skull deep with a large orbit and there is a supraorbital
(Text-fig. 3) as in Heterodontosaurus (see Crompton & Charig 1962, Galton 19700),
Parksosaurus (Parks 1926, Galton in press), Dysalotosaurus (Janensch 1955) and in
138
THE WEALDEN HYPSILOPHODON
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MAMMALIA
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breviations:F, femur
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I4o THE WEALDEN HYPSI LOPHODON
the skulls referred to Laosaurus and Dryosaurus by Gilmore (1925). The snout is
longer with a more elongated tooth row and a proportionally smaller orbit in Camp-
tosaurus (Gilmore 1909), Iguanodon (Hooley 1925) and hadrosaurs (see Lull & Wright
1942. (Hadrosaurs will be mentioned only when there is a difference from Iguano-
don.)
The posterior process of the premaxilla is short and slender as in thecodontians
and, since it does not contact the prefrontal or the lachrymal, the nasal is not com-
pletely separated from the maxilla. This is also the case in Parksosaurus where this
process, though short, is broad and has a good suture with the maxilla. The
posterior process is long and contacts the prefrontal and lachrymal in Heterodonto-
saurus, Dysalotosaurus, Camptosaurus and Iguanodon.
In thecodontians the antorbital fenestra is large (Romer 1956) as was also the
case in Heterodontosaurus. It is quite large in Hypsilophodon but is much smaller in
Laosaurus and Dryosaurus and practically non-existent in Parksosaurus, Dysaloto-
saurus, Camptosaurus and Iguanodon. The quadratojugal was not excluded from
the margin of the lower temporal fenestra by the jugal which, as a result, did not
contact the quadrate. The jugal makes this contact and the quadratojugal is small
in Parksosaurus, Dysalotosaurus, Camptosaurus and Iguanodon. The large size of
the quadratojugal of Hypsilophodon (and the consequent reduction of the lower
temporal fenestra) is a specialized feature.
Thecodontians had premaxillary teeth but these were lost in most ornithischians.
They were retained in Hypsilophodon, Heterodontosaurus, Thescelosaurus (see
Sternberg 1940, Galton in press a), Stegoceras (see Gilmore 1924), the ceratopsians
Protoceratops and Leptoceratops (see Brown & Schlaikjer 1940) and the nodosaur Sil-
visaurus (Eaton 1960). The general form of the thickly enamelled side of the maxil-
lary and dentary teeth resembles that of Dysalotosaurus, Laosaurus (see Marsh
1896), Camptosaurus and Iguanodon. There is a well-defined central ridge on each
dentary tooth of Hypsilophodon as in Laosaurus. There is a strong central ridge
on each maxillary tooth as well in Dysalotosaurus while in Camptosaurus the strong
central ridge is restricted to the maxillary teeth. The thickly enamelled surface
does not resemble that of Heterodontosaurus, Fabrosaurus (Ginsburg 1964), Parkso-
saurus or Thescelosaurus.
The lack of comparative data for the palate of thecodontians and of other lower
ornithopods makes it difficult to recognize which characters of the palate of Hypsilo-
phodon are generalized ; it would appear that the palatines and pterygoids of
opposite sides did not meet at the midline.
In the vertebral column the neural spines are low as in Dysalotosaurus (see
Janensch 1961) and they are progressively taller in the series Parksosaurus, Thescelo-
saurus, Camptosaurus (see Gilmore 1912) and Iguanodon (see Casier 1960). The first
chevron is reduced to a nubbin while in Dysalotosaurus it is much longer but it is
absent in Thescelosaurus and Camptosaurus.
Dermal armour is present in most thecodontians and, if the plates described by
Nopcsa (1905) were correctly described (see page 102), then Hypsilophodon is the only
ornithopod in which dermal armour has been reported. In stegosaurs and ankylo-
saurs dermal plates formed a strong armour.
ISLE OF WIGHT, ENGLAND 141
In the pelvis the ilium is low as in Parksosaurus. The ilium is progressively deeper
in the series Thescelosaurus, Dysalotosaurus, Camptosaurus and Iguanodon. The
prepubic process of Hypsilophodon is not short as in the Triassic ornithischians
Fabrosaurus and Heterodontosaurus (Crompton & Charig, personal communication)
which probably represent the primitive ornithischian condition (see Galton 19700).
The rod-like prepubic process of Hypsilophodon resembles that of Dysalotosaurus and
the anterior end is not expanded slightly as it is in Thescelosaurus (Galton in press a)
and Dryosaurus. In Camptosaurus the prepubic process is deep and transversely
flattened and this is even more marked in Iguanodon. The postpubic rod extends
to the end of the ischium as in Thescelosaurus, Dysalotosaurus and Camptosaurus but
it is much shorter in iguanodontids, hadrosaurs, psittacosaurids and ceratopsians.
The obturator process of the ischium is on about the same position on the shaft as it
is in Thescelosaurus. The obturator process is progressively more proximal in the
series Parksosaurus, Hypsilophodon, Dysalotosaurus, Camptosaurus and Iguanodon.
The distal part of the ischium is straight, flat and blade-like as it is in Thescelosaurus
and Parksosaurus. In Dysalotosaurus, Camptosaurus and Iguanodon the ischium
curves ventrally and the distal part is much more massive.
The manus has five digits with four phalanges on the third digit. The latter large
number has been reported only in Thescelosaurus, Psittacosaurus (see Osborn 1924)
and in Protoceratops, Leptoceratops and Monoclonius (Brown & Schalikjer 1940) . The
distal end of the femur has practically no anterior condylar groove. This groove is
shallow in Thescelosaurus and Parksosaurus and becomes progressively deeper in the
series Dysalotosaurus, Dryosaurus, Camptosaurus and Iguanodon while in hadrosaurs
the edges meet above the deep cleft. Posteriorly the outer condyle is almost as large
as the inner while in the above-mentioned genera the outer condyle is sheet-like and
much smaller than the inner condyle. The cnemial crest of the tibia is small as in
Pisanosaurus (see Casamiquela 1967) and Dysalotosaurus ; it is much larger in
Parksosaurus, Thescelosaurus, Camptosaurus and Iguanodon. In the pes a rudi-
mentary fifth metatarsal is present as is the case in many other ornithischians.
At first sight it would appear that the cursorial adaptations of Hypsilophodon
would be specialized rather than generalized features for ornithischians. However,
the hindlimb of Pisanosaurus (Casamiquela 1967) from the Triassic Ischigualasto
Formation of Argentina was probably more highly adapted for fast running than was
that of Hypsilophodon. The tibia and third metatarsal of Pisanosaurus are both
slender with a metatarsal to tibia ratio of 0-59 as against 0-53 for Hypsilophodon.
The metatarsus of Triassic ornithischians from the Connecticut Valley (Anomoepus,
Sauropus, see Lull 1953) was also very slender and elongated. Skeletons of Fabro-
saurus and Heterodontosaurus collected from the Upper Triassic of southern Africa
show that both were bipedal and were adapted for fast running (Crompton, personal
communication; see below : 149). The proximal position of the fourth trochanter
of the femur and the elongate tibia and third metatarsal of the hindlimb of
Hypsilophodon appears to have been more generalized than any other post-Triassic
ornithischian. Increased size in ornithopods appears to have been correlated with
a more distal position for the fourth trochanter of the femur and a relatively shorter
tibia and third metatarsal (Table V). This probably occurred several different times
10
I42 THE WEALDEN HYPSILOPHODON
during the history of the group : in Camptosaurus, in the line to Iguanodon and the
hadrosaurs (Rozhdestvenskii (1966), in the pachycephalosaurids and in Thescelosaurus
(see Galton in press a) . A reversion to quadrupedality and increased size occurred
in the line close to Psittacosaurus that led to ceratopsians and in the lines to
ankylosaurs and stegosaurs (Text-fig. 64).
From the above survey it is apparent that Hypsilophodon retained many features
of a generalized nature for ornithopods and, as a result, probably for ornithischians
as a whole. Hypsilophodon occurred too late in time to have been directly ancestral
to ankylosaurs, stegosaurs and most of the ornithopods. Rozhdestvenskii (1966)
has shown that hadrosaurs were probably derived from Iguanodon that, like the most
primitive pachycephalosaurid (see Galton, 1971), was a sympatric contem-
porary of Hypsilophodon. The large size of the maxilla and quadratojugal would
debar Hypsilophodon from the direct ancestry of Parksosaurus. Its skull is inade-
quately known but it is possible that Thescelosaurus may have been derived from
Hypsilophodon by a broadening of the frontals, a decrease in the size of the orbit,
the specialization of the teeth and by graviportal modifications of the postcranial
skeleton (see Galton in press a). The psittacosaurids and ceratopsians could have
evolved from a form that was similar to Hypsilophodon but in which the prepubic
process was much smaller.
The restricted geographical and stratigraphical occurrence of Hypsilophodon is
obviously the result of accidents of the fossil record as known to date. The discovery
of representatives of this genus in Jurassic or even in Triassic rocks is a distinct
possibility. If the Triassic ancestor had a larger antorbital fenestra, a smaller
quadratojugal, a small prepubic process and a more massive postpubic rod then it
would make a good structural ancestor for ah1 Jurassic and Cretaceous ornithischians
(see below : 149).
X. SUMMARY
Several articulated specimens of Hypsilophodon were prepared mechanically and
with acetic acid. Although no new material was included this enabled a more
thoroughly detailed description of the osteology to be made. Only a few features
are still uncertain : the contacts between the palatine, parasphenoid and vomer ;
the transverse relationships between the tooth rows of the maxillae and lower jaw ;
the form of the complete fibula ; the number and shape of some of the carpal bones
and of the phalanges of the fifth digit of the manus.
The femur of Camptosaurus valdensis Lydekker (1889) is referred to Hypsilophodon
foxii. It represents the largest individual recognized to date and was from an animal
of about 2-28 m.
The paroccipital process of Hypsilophodon appears to be formed completely by
the opisthotic, with the exoccipital restricted to the lateral part of the occipital
condyle. This is in contrast to the position in the hadrosaur described by Langston
(1960) in which the exoccipital appears to form most of the paroccipital process.
Contrary to previous reports the skull has a supraorbital and also a sclerotic ring
which was presumably essential for accommodation as is the case in living sauropsids.
ISLE OF WIGHT, ENGLAND 143
The areas of attachment of the jaw muscles were, apart from those of the M. ptery-
goideus dorsalis and ventralis, similar to those described by Ostrom (1961) for the
hadrosaur Corythosaurus. In Hypsilophodon the dorsal part of the coronoid is
covered with very well-developed insertion markings which support Ostrom's
contention that the M. pseudotemporalis inserted there. The area on the braincase
of Corythosaurus where the M. levator bulbi may have originated could be prootic
and basisphenoid rather than laterosphenoid. Originally this surface was for the M.
protractor pterygoidei but, when the skull became akinetic, this surface may have
become free and was then occupied by the M. levator bulbi. The M. protractor
pterygoidei probably originated on the equivalent area in Hypsilophodon, the skull
of which was possibly mesokinetic, metakinetic and amphistylic. The large antor-
bital fossa opened posteriorly across the floor of the orbit and was presumably for
the anterior part of the M. pterygoideus dorsalis, the pterygoideus D, or possibly
for a postulated equivalent of the M. pterygoideus ventralis. The moment arm of
the jaw adductor muscles was lengthened by the presence of a large coronoid process
and an off-set articulation with the quadrate. The anterior part of the premaxillae
and the predentary were enclosed by a horny beak which was used to crop plants.
The mouth was probably small with a large cheek pouch lateral to the tooth rows.
The maxillary teeth are thickly enamelled on the lateral surface and they curve
medially while with the dentary teeth the reverse is the case. The thickly enamelled
edge was much more resistant than the rest of the crown and formed a sharp leading
edge to an obliquely inclined occlusal surface between which and its fellow there was
a high shear component. The cutting effect of this edge was enhanced by the pre-
sence of serrations produced by vertical and parallel ridges on the thickly enamelled
surface. The foramina on the medial surface of the tooth-bearing bones, one per
tooth, represent a preadaptation for the development of high alveolar walls.
There is a surprising amount of variation, the most interesting of which is the pre-
sence of an additional sacral rib in some individuals ; this supports the contention
of von Beneden (1881) and Nopcsa (1918, 1929) that the sacral count can vary within
an ornithopod species. The massive first sacral rib backed the slender pubic
peduncle of the ilium and keyed that bone to the pubis. The humerus could have
been held vertically and the fifth digit of the manus may have been well formed
and opposable.
Hypsilophodon was clearly bipedal as shown by the fore- to hindlimb ratio, the
hindlimb to trunk ratio and the restriction of cursorial adaptations to the hindlimb.
The arguments advanced to put Hypsilophodon up in the trees, the position it occu-
pies in every textbook, are reviewed historically and discussed under the separate
regions of the body concerned. The first metatarsal was closely applied along all its
length to the adjacent part of metatarsal II. The first digit of the pes was not
opposable and all the phalanges closely resemble those of other dinosaurs. The rela-
tively small size of the grasping manus would have restricted its usefulness in climbing
and the fore-arm space was not uniquely enlarged by a bowed radius. The rigid
tail with its sheath of ossified tendons would have been useful as an aid to balancing
and steering while running on the ground. If dermal armour was present then this
was more protection than possessed by any other ornithopod. Far from having
I44 THE WEALDEN HYPSILOPHODON
limited running capabilities Hypsilophodon was the ornithopod most highly adapted
for fast running if the ratios of the length of the femur : tibia, femur : third metatar-
sal and the position of the fourth trochanter mean anything. The values for the
first two ratios fall in the middle range of those for the living ungulates that Gregory
(1912) considered cursorial.
Although Hypsilophodon is from the Lower Cretaceous it has retained several
features that may be generalized for ornithischians. The skull has a short snout
with the retention of premaxillary teeth, the orbit is large and there is a supraorbital.
The premaxilla has a short and slender posterior process that does not meet the pre-
f rental or lacrymal and, as a result, the maxilla meets the nasal. The quadratojugal
is not excluded from the margin of the lower temporal fenestra by the jugal which,
as a result, does not contact the quadrate. The neural spines are low, a first chevrons
(rudimentary) is present and there may have been dermal armour. The manus has
five digits with four phalanges on the third digit. The ilium is low, the postpubic
rod is long and the distal half of the ischium is straight and blade-like. The fourth
trochanter is placed proximally on the femur ; the distal end of the femur has prac-
tically no anterior intercondylar groove while posteriorly the outer condyle is almost
as large as the inner condyle. The long tibia has a small cnemial crest. The fifth
metatarsal is vestigial but the first to fourth are relatively elongate and the hind-
limb is adapted for fast running. Structurally Hypsilophodon is quite similar to
the hypothetical ancestor of the other ornithischians of the Jurassic and Cretaceous.
XI. ACKNOWLEDGEMENTS
This paper is based on work done in the Zoology Department, King's College,
University of London, which was made possible by a three-year Research Student-
ship from the Department of Scientific and Industrial Research (subsequently the
Natural Environment Research Council). I am grateful to the following people
who lent me material : Dr A. J. Charig of the British Museum (Natural History)
(material of Hypsilophodon with permission to prepare it in acid, the holotype was
kindly prepared by Mr R. Croucher) ; Mr Grapes of the Sandown Museum, Isle of
Wight (foot) and Dr P. L. Robinson of University College London (three partial
skeletons). I thank Drs A. J. Charig of the British Museum (Natural History), J. H.
Ostrom of Yale University, New Haven, P. L. Robinson of University College Lon-
don, D. A. Russell of the National Museum of Canada and A. D. Walker of the
University of Newcastle upon Tyne for reading the manuscript at various stages
and for all their comments. Dr A. W. Crompton of Harvard University kindly
provided information about the Triassic ornithischian material collected from
southern Africa. Finally my best thanks must go to Dr C. Barry Cox of King's
College London for his constant help and encouragement during the course of this
work.
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NOTE
Several papers of related interest have appeared in the three years since the
manuscript of this article was last revised. I have given a full discussion of the
mode of life of Hypsilophodon (Galton 1971!)) with figures illustrating the comparisons
made above (: 133-137) and with stereo-photographs of the manus and pes of RiQ6
in dorsal view ; an abstract of this paper appeared a little earlier (1971 a). Two
other papers (Galton 1973, Galton in press) include reconstructions of the skull of
Hypsilophodon in ventral and dorsal view respectively and figures of the skull.
Thulborn (1970, 1971, 1972) gives a detailed description of the anatomy of the
Upper Triassic ornithischian Fabrosaurus australis and, on the basis of my figures of
150 THE WEALDEN HYPSILOPHODON
Hypsilophodon (Gallon 1967), refers Fabrosaurus to the family Hypsilophodontidae.
However, my concept of this family (Galton 19710, b, 1972, 1973 in press, in press a)
is not as all-embracing as Thulborn's (1970, 19700, 1971, 19710, 1972) who includes
all cursorial ornithopods with premaxillary teeth plus Thescelosaurus (for genera see
Thulborn 1972, fig. 14). I agree with Thulborn (1970, 1971, 1972) that the Upper
Triassic Fabrosaurus is very similar to the archetypal ornithischian from which all
other ornithischians were originally derived. Indeed, the skull of Fabrosaurus
with its flat maxilla, slender dentary and marginally positioned maxillary and
dentary teeth (see Thulborn 1970, Galton 1973) is so primitive that I place that genus
(along with Echinodon Owen from the Lower Cretaceous of England) in a separate
family, the Fabrosauridae (Galton 1972). This family resembled living reptiles in
not having muscular cheeks. In all other ornithischians described to date there is a
large space lateral to the tooth rows which is overhung by the maxilla and floored
by the massive dentary ; it is presumed that this space was bordered by cheeks (as
noted on page 121 for Hypsilophodon) which prevented the loss of food from the sides
of the jaws, as would otherwise have occurred when resistant plant material was
chewed repeatedly. I attribute the spectacular success of ornithischian dinosaurs,
the dominant 'small to medium' (up to 10 m) sized terrestrial herbivores of the
Jurassic and Cretaceous periods (about 125 million years), to their development of
cheeks (Galton, 1972, 1973).
Thulborn (1970, 19700, 1971, 19710, 1972) refers Heterodontosaurus (as ' Lycor-
hinus') to the family Hypsilophodontidae. Heterodontosaurus has cheek teeth
with planar wear surfaces and there is a caniniform tooth on each premaxilla and
dentary (see Crompton & Charig 1962, Thulborn 19700). I consider (Galton 1972)
that these dental specializations justify the retention of the family Heterondonto-
sauridae, to which I also refer Geranosaurus and Lycorhinus. Thulborn (1970,
19700, 1971, 1972) follows current practice in placing Thescelosaurus (graviportal,
premaxillary teeth ; see Sternberg, 1940) in the family Hypsilophodontidae and
referring Dysalotosaurus (cursorial, no premaxillary teeth ; see Janensch, 1955) to
the family Iguanodontidae. These taxonomic assignments are based on the respect-
ive presence or absence of premaxillary teeth, but I consider that this criterion should
not be used to determine which genera should be included in the family Hypsilo-
phodontidae (see Galton 1972). The skull of Dysalotosaurus is very similar to that
of Dryosaurus (cursorial, no premaxillary teeth) ; I therefore place both those genera
in the Hypsilophodontidae and refer Thescelosaurus to the Iguanodontidae (Galton
1972, in press, in press 0).
The cursorial ornithopods of conservative aspect should be referred to the family
Hypsilophondontidae, diagnosed as follows :
Head small, snout short, orbits large ; no large rostral beak, no caniniform teeth,
maxillary and dentary teeth inset (longitudinal recess to maxilla, massive dentary)
and with randomly formed wear surfaces which are not all in the same plane ;
distal part of hind limb elongate (Galton 1972, in press). The genera and
specimens that I refer to this family are shown in the phyletic chart (Text-fig. 64)
and the relationships shown are based largely on the form of the femur (for discussion
of various aspects of this chart see Galton 1972, in press, in press 0).
ISLE OF WIGHT, ENGLAND
CURSORIAL
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FIG. 64. Phylogeny of the Ornithopoda ; modified from Galton (1972). Diagram to
show phylogenetic relationships and the nature of the fossil record of lower ornithopods.
The ages of the different genera are based on data in Charig (1967) and the stratigraphic
distribution is by stages, the initials of which are given in the third column. Abbrevia-
tions : Classificationary units : ANKYL, Ankylosauria ; CERAT, Ceratopsia ; FABR,
Fabrosauridae ; HADR, Hadrosauridae ; HETER, Heterodontosauridae ; HYPSIL,
Hypsilophodontidae ; IGUAN, Iguanodontidae ; PACHY, Pachycephalosauridae ;
PSITT, Psittacosauridae ; STEG, Stegosauria. Genera : C, Camptosaurus ; CA,
' Camptosaurus ' leedsi, Ri993 ; CU, Cumnoria ('Camptosaurus') prestwichi, D, Dryo-
saurus and Dysalotosaurus : E, Echinodon ; F, Fabrosaurus ; G. Geranosaurus and Ly-
corhinus, H, Heterodontosaurus ; HY, Hypsilophodon ; I, Iguanodon ; L, Laosaurus ;
LM, 'Laosaurus' minimus ; P, Pisanosaurus ; PA, Pachycephalosaurus : PK, Parkso-
saurus ; PS, Psittacosaurus ; S, Stegoceras ; T, Tenontosaurus ; TH, Thescelosaurus ;
W, Wealden hypsilophodont (Ri84, Ri85, 36509, see above, p. 7 ; to be described
elsewhere) ; Y, Yaverlandia (Galton 1971). Actual fossil record of ornithopods indicated
by ; no fossil record indicated by but genera in the same vertical line are
closely related ; postulated relationships indicated by
152
THE WEALDEN H YPSILOPHODON
In this connection, however, it must be pointed out here that the Iguanodontidae
as presently constituted are probably not a natural group, a monophyletic taxon.
Text-fig. 64 shows that the ' family ' comprises three lines of graviportal ornithopods
arising independently from the Hypsilophodontidae : the Iguanodontidae sensu
stricto (with Cumnoria, Iguanodon and Tenontosaurus), a line leading to Camptosaurus,
and a line leading to Thescelosaurus.
OTHER REFERENCES
CHARIG, A. J. 1967. Subclass Archosauria. In Harland, W. B. et al. (Eds.) The fossil record.
London (Geological Society of London) : 708-718, 725-731.
GALTON, P. M. 19710. Hypsilophodon, the cursorial non-arboreal dinosaur. Nature, Lond.,
231 : 159-161, 2 figs.
— 19716. The mode of life of Hypsilophodon, the supposedly arboreal ornithopod dinosaur.
Lethaia, Uppsala, 4 : 453-465, 5 figs.
— 1972. Classification and evolution of ornithopod dinosaurs. Nature, Lond., 239 : 464-466,
i fig.
— 1973. The cheeks of ornithischian dinosaurs. Lethaia, Uppsala, 6 : 67-89, 7 figs.
THULBORN, R. A. 1970. The skull of Fabrosaurus australis, a Triassic ornithischian dinosaur.
Palaeontology, London, 13 : 414-432, 9 figs.
19700. The systematic position of the Triassic ornithischian dinosaur Lycorhinus angus-
tidens. Zool. J. Linn Soc., London, 49 : 235-245, 5 figs.
— 1971. Tooth wear and jaw action in the Triassic ornithischian dinosaur Fabrosaurus.
J. Zool., Lond., 164 : 165-179, 9 figs.
— 19710. Origin and evolution of ornithischian dinosaurs. Nature, Lond., 234:75-78,
4 figs.
1972. The post-cranial skeleton of the Triassic ornithischian dinosaur Fabrosaurus
australis. Palaeontology, London, 15 : 29-60, 14 figs.
INDEX
The page numbers of the principal references are printed in bold type ; an asterisk (*) denotes
a figure.
All anatomical terms refer to the species Hypsilophodon foxii Huxley.
abducent nerve, 104
accessory elements of skull, 46-7
adductor mandibulae muscles, 110-2
anatomical evidence that Hypsilophodon was
arboreal, 133-7
anatomy, cranial, 103-22
post-cranial, 122-30
Anatosaurus, 46, 125
Anchisaurus, 134, 139
angular, 39
Anomoepus, 134, 141
Antilocapra americana, 139
Antilope cervicapra, 139
antorbital fenestra, 117-9
recess, 18
appendicular skeleton, 72-102
arboreal condition in Hypsilophodon, 130-7
armour, dermal, 102, 136, 140
articular, 41
articulation of limbs, 124-7
astragalus, 97, 98*, 99*
atlas, 48-50, 48*, 49*
axis, 48*, 49*, 50-1
balancing organ, rigid tail as, 136
Basiliscus, 128
basioccipital, 22
basisphenoid, 26-7
bipedal pose, 127-30
bones of skull and jaw, 21-41
brachial movements, wider range possible,
135-6
braincase, 34*
foramina of, 103-5
Calamospondylus foxi, 7, 18
calcaneum, 97, 98*, 99*
INDEX
Camptosaurus, 44*, 103, 105, 117, 122-3, Z32>
134, 136, 140-2, 152
browni, 122
depressus, 122
dispar, 122
leedsi, 103
nanus, 136, 138
prestwichi, 123
valdensis, 4, 7, 102-3, 142 ; pi. 2, fig. 4
carpals, 80-3, 81*
caudal vertebrae, 63, 65
cervical vertebrae 3 to 9, 51, 52*, 53*
chevrons, 65
Coelophysis, 134-5, 137
bauri, 139
condyles, 19
constrictor dorsalis muscles, 112-4
ventralis muscles, 114
coracoid, 12*, 13, 73-4, 73*, 74*, 75*
Corythosaurus, 46, 143
Cowleaze Chine, Isle of Wight, 5, 7, 9-10,
15-17
cranial anatomy, 103-21
Ctenosaura, 113, 116
Cuckfield, Sussex specimen not Hypsilo-
phodon, 7
Cumnoria, 152
Cyrena, 16
Deinonychus, 136
Dendrolagus, 131, 133, 136
dental formula, 41
dentary, 39
teeth, 18, 42-3, 44*
dentition, diagrammatic cross-section, 120*
depressor mandibulae, musculus, 114
dermal armour, 102, 136, 140
dorsal vertebrae, 54*, 55*, 56-7, 59*
Dryosaurus, 103, 140-1, 150
altus, 138
Dysalotosaurus, 44, 57, 105, 117, 123-4,
134-8, 140-1, 150
Echinodon, 150
ectopterygoid, 36-7
Eohippus, 137, 139
Equus caballus, 137, 139
Euparkeria, 117-8
eye, 106-10 ; see also sclerotic ring
exoccipital, 22
Fabrosaurus, 5, 117, 140-1, 150
australis, 149
facial nerve, 104
fauna associated with Hypsilophodon, 17-18
features, generalized, of Hypsilophodon,
137-42
femur, 12*, 14, 19, 94*, 95*, 95-6 ; pi. 2,
fig- 4
fourth trochanter index, 13
fenestra, antorbital, 117-9
post- temporal, 105-6
fibula, 96-7, 98*
figured specimens of Hypsilophodon,
BM(NH) numbers of, 10-2
foramina, of braincase, 103-5
special, 44-5
forelimb, forearm, 75-83, 124-6, 136
fossa, post- temporal, 105-6
Fox, W., collection, 7-8
frontal, 31-2
Gazella dorcas, 139
Geranosaurus, 150
girdle, pectoral, 72-5
pelvic, 83-95
Goniopholis, 18
Gorgosaurus, 137, 139
grasping capabilities of Hypsilophodon, 133-5
hadrosaurs, 140-2
Hesperosuchus, 134
Heterodontosaurus, 107, in, 117, 137, 140-1,
150
hexapleural type sacrum, 60 -i
hindlimb, 95-102, 126-7, J41
measurements and ratios in dinosaurs and
cursorial ungulates, 138-9
Hulke, J. W., collection, 9-10
humerus, 12*, 13, 18, 75, 77*, 78, 78*
hyoid apparatus, 46
Hypsilophodon from Wealden of Isle of
Wight, 1-152, passim
foxii, 5, 18-19
holotype, 19, 20*
paratype, 19
specimens used for osteology and re-
constructions, 19
Hypsilophodon bed, 8, 15-18
Hypsilophodontidae, 18-19, *5°, !52
Hyracotherium, see Eohippus
Iguanodon, 5, 7, 18, 44, 71, 102, in, 122,
124-5, 132, 134-6, 140-2, 152
atherfieldensis , 18, 103, 124, 136, 138
.bernissartensis, 19, 122-3
foxi, 5
mantelli, 5, 18, 122-3
Iguanodontidae, 150, 152
INDEX
ilium, 12*, 13, 83, 87, 90*, 91*
individual variation of Hypsilophodon, 122-3
intermedium, see carpals
ischium, 12*, 14, 19, 89, 93*, 95
jaw, lower, 37*, 38-9 ; see also mandibular
ramus
action, 119-21
musculature, 110-4
lines of action, 108*
jugal, 18, 32-3
kinetism, 114-6
Kritosaurus, 125
incurvimanus, 138
Lacerta, 106
lachrymal, 35
Lambeosaurus, 46
Laosaurus, 103, 140
laterosphenoid, 27
Leptoceratops, 140-1
localities of Hypsilophodon, 17
lower jaw, 38-41
Lycorhinus, 150
Macropus, 131
mandibular muscles, see jaw musculature
ramus, 37*, 40*
Mantell, G. A., collection, 7
manus, 14-15, 80*, 141
grasping capabilities, 135
material of Hypsilophodon, 6-10
maxilla, 30-1
maxillary teeth, 18, 42-3, 43*
measurements of Hypsilophodon, 12-15
Mesohippus, 137, 139
metacarpals, 82*, 83
metatarsals, 14-15, 99*, 101
methods, 6-15
Monoclonius, 141
musculature of jaw, 110-4
musculus adductor mandibulae externus,
IIO-I
pars medialis, in
pars profundis, in
pars superficialis, no-i
musculus adductor mandibulae internus,
III-2
musculus adductor mandibulae posterior, 112
musculus depressor mandibulae, 114
musculus pseudotemporalis, 1 1 1
musculus pterygoideus, 112
narial openings, 18
nasal, 31
Neohipparion whitneyi, 139
nerves of skull, 103-5
new sacral rib, 61
obturator process, 18
Odocoileus hemionus, 139
Ophisaurus, 107
opisthotic, 22, 26
orbit, see eye, sclerotic ring
orbitosphenoid, 27
Ornithosuchia, 18-19
Ornithosuchian dinosaur Hypsilophodon,
1-152
Ornitholestes, 135
hermanni, 139
Ornithomimus, 107
brevitortius , 139
Ornithopoda, 18-19
Ornithosuchus, 118
ossified tendons, 71-2
osteology, 18-102
pachycephalosaurids, 142
palatine, 37-8, 140
Paludina, 16
parasphenoid, 27
parietal, 31
Parksosaurus, 46, 57, 72, 107, 117, 119, 124,
134-7, 140-2
warreni, 138
paroccipital process, 105-6
pectoral girdle, 72-5
pelvic girdle, 83-95, 84*, 85*, 86*, 88*, 141 ;
see also ilium, ischium, etc.
pelvic region, reconstruction, 88*
pes, 14-15, ioo*, 131* ; pi. 2, fig. 3
grasping capabilities, 133-5
phalanges, 14-15, 83, 99*, 101-2
Pisanosaurus, 141
Plateosaurus, 105, 134, 139
Polacanthus foxii, 18
Poole, H. F., collection, 10
pose of Hypsilophodon, quadrupedal or
bipedal ?, 127-30
post-cranial anatomy, 122-30
postorbital, 35-6
post-temporal fenestra or fossa, 105-6
posture of limbs, 124-30
of vertebral column, 127-30
prearticular, 41
predentary, 38*, 38-9
tooth, 42*
prefrontal, 35
premaxilla, 18, 27, 30
premaxillary teeth, 18, 41-2
INDEX
preparation of material, 6, 142
proatlas, 48, 48*, 49*
Procompsognathus triassicus, 131
prootic, 26
Protiguanodon, 138
Protoceratops, 72, 78, in, 140-1
andrewsi, 122
psittacosaurids, 142
Psittacosaurus, 134, 138, 141-2
pterygoid, 36
pubis, 12*, 14, 87, 89, 92*
quadrate, 18, 33
quadrotojugal, 18, 33
quadrupedal pose of Hypsilophodon, 127-30
radius, 13, 79*, 80, 136
reconstructions of Hypsilophodon, 129*
replacement teeth, 44-5
sequence, 45-6
ribs, see vertebral column
sacral, 60
first, 123-4
running capabilities of Hypsilophodon, 136-7
sacral ribs, 18, 60
first, 123-4
sacral vertebrae, 18, 57-60
sacrum, hexapleural type, 59*, 60- 1
pentapleural type, 58*
other variations in, 61, 63
Sauropus, 141
scapula, 12*, 13, 18, 72-3, 73*, 74*, 75*
sclerotic ring, 46-7, 47* ; see also eye
Silvisaurus, 140
skeleton, see osteology
skull, 20*, 2i*, 21-38, 23*. 24*, 25*, 28*,
29*, 32*, 108*, 109*, 137, 140 ; plate
i ; pi. 2, figs. 1-2 ; see also braincase,
cranial anatomy
snout, 137, 140
Sphenodon, 47, 106, 116
splenial, 39
squamosal, 33, 35
Stagonolepis, 117-8
stapes, 47
Stegoceras, 140
(Troodon) validus, 138
Stegosaurus, 127
sternum, 74-5, 76*
stratigraphy of Hypsilophodon bed, 15-17
streptostyly, 116-7
Struthiomimus , 135, 137, 139
supraoccipital, 21-2
supraorbital, 35, 137
surangular, 39, 41
tail, rigid, as balancing organ, 136
tarsals, 97, 99*, 100-1
teeth, 18, 41-6, 140
sequence of replacement, 45-6
tendons, ossified, 70*, 71*, 71-2
Tenontosaurus, 152
Thescelosaurus, 57, 66, 83, 123-4, I27> J32~4>
136, 140-2, 150, 152
edmontonensis , 138
neglectus, 122, 138
tibia, 14, 96, 98*
Tragulus napu, 137, 139
trigeminal foramen, 104
Trionyx, 18
trochanters, 19
ulna, 13, 78, 79*, 136
Unio, 1 6
Uromastix, 116
Varanus, 115
variation, individual, in Hypsilophodon,
122-3
vertebrae, caudal, 63-71, 66*, 67*, 68*, 69*,
70*
cervical, 51
dorsal, 56-7, 62*, 64*
sacral, 57-60, 62*, 63*, 64*
vertebral column, 48-70, 140
posture, 127-30
vomer, 38
Wealden of Isle of Wight, Hypsilophodon
from, 1-152
PETER M. GALTON, B.Sc., Ph.D.
Department of Zoology
KING'S COLLEGE LONDON UNIVERSITY
STRAND, LONDON, W.C. 2
Present address :
Department of Biology
UNIVERSITY OF BRIDGEPORT
BRIDGEPORT, CONN. 06602, U.S.A.
Peabody Museum of Natural History
YALE UNIVERSITY
NEW HAVEN, CONN., U.S.A.
PLATE i
Hypsilophodon foxii
FIG. i . Skull R2477, dorsal view. Compare with Text-fig. 56.
FIG. 2. Skull R2477, palatal view. Compare with Text-fig. 6A.
FIG. 3. Skull R2477, left lateral view. Compare with Text-fig. 4 A.
FIG. 4. Skull R2477, right lateral view. Compare with Text-fig. 4A.
Scale line represents 5 cm.
Bull. Br. Mus. nat. Hist. (Geol.) 25, i
PLATE i
CN
PLATE 2
Hypsilophodon foxii
FIG. i. Skull R2477, dorsal view of palate and braincase. Compare with Text-fig. 56.
FIG. 2. Skull R2477, medial view, compare with Text-figs. 46, 6oD.
FIG. 3. Pes Rig6, dorsal view of left pes.
FIG. 4. Femur Ri67, ' Camptosaurus valdensis' , from a large individual of Hypsilophodon
foxii. a, anterior view ; b, posterior view.
Scale lines represent 5 cm.
Bull. Br. Mus. nat. Hist. (Geol.) 25, i
PLATE 2
_Q
CN
A LIST OF SUPPLEMENTS
TO THE GEOLOGICAL SERIES
OF THE BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
1. Cox, L. R. Jurassic Bivalvia and Gastropoda from Tanganyika and Kenya.
Pp. 213 ; 30 Plates ; 2 Text-figures. 1965. £6.
2. EL-NAGGAR, Z. R. Stratigraphy and Planktonic Foraminifera of the Upper
Cretaceous — Lower Tertiary Succession in the Esna-Idfu Region, Nile Valley,
Egypt, U.A.R. Pp. 291 ; 23 Plates ; 18 Text-figures. 1966. £10.
3. DAVEY, R. J., DOWNIE, C., SARJEANT, W. A. S. & WILLIAMS, G. L. Studies on
Mesozoic and Cainozoic Dinoflagellate Cysts. Pp. 248 ; 28 Plates ; 64 Text-
figures. 1966. £7.
APPENDIX. DAVEY, R. J., DOWNIE, C., SARJEANT, W. A. S. & WILLIAMS, G. L.
Appendix to Studies on Mesozoic and Cainozoic Dinoflagellate Cysts. Pp. 24.
1969. Sop.
4. ELLIOTT, G. F. Permian to Palaeocene Calcareous Algae (Dasycladaceae) of
the Middle East. Pp. in ; 24 Plates ; 17 Text-figures. 1968. £5.12^.
5. RHODES, F. H. T., AUSTIN, R. L. & DRUCE, E. C. British Avonian (Carboni-
ferous) Conodont faunas, and their value in local and continental correlation.
Pp. 315 ; 31 Plates ; 92 Text-figures. 1969. £11.
6. CHILDS, A. Upper Jurassic Rhynchonellid Brachiopods from Northwestern
Europe. Pp. 119 ; 12 Plates ; 40 Text-figures. 1969. £4.75.
7. GOODY, P. C. The relationships of certain Upper Cretaceous Teleosts with
special reference to the Myctophoids. Pp. 255 ; 102 Text-figures. 1969.
£6.50.
8. OWEN, H. G. Middle Albian Stratigraphy in the Anglo-Paris Basin. Pp. 164 ;
3 Plates ; 52 Text-figures. 1971. £6.
9. SIDDIQUI, Q. A. Early Tertiary Ostracoda of the family Trachyleberididae
from West Pakistan. Pp. 98 ; 42 Plates ; 7 Text-figures. 1971. £8.
10. FOREY, P. L. A revision of the elopiform fishes, fossil and Recent. Pp. 222 ;
92 Text-figures. 1973. £9.45.
Printed in Great Britain by John Wright and Sons Ltd. at The Stonebridge Press, Bristol 884 sNU
THE TAXONOMY AND ^
MORPHOLOGY OF PUPPIGERUS
CAMPERI (GRAY), AN EOCENE SEA-
TURTLE FROM NORTHERN EUROPE
R. T. J. MOODY
BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
GEOLOGY Vol. 25 No. 2
LONDON: 1974
22 JULIS
THE TAXONOMY AND MORPHOLOGY OF
PUPPIGERUS CAMPERI (GRAY), AN EOCENE
SEA-TURTLE FROM NORTHERN EUROPE
BY
RICHARD THOMAS JONES MOODY
Kingston Polytechnic
Pp. 153-186 ; 8 Plates, 15 Text-figures
BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
GEOLOGY Vol. 25 No. 2
LONDON: 1974
THE BULLETIN OF THE BRITISH MUSEUM
(NATURAL HISTORY), instituted in 1949, is
issued in five series corresponding to the Departments
of the Museum, and an Historical series.
Parts will appear at irregular intervals as they
become ready. Volumes will contain about three or
four hundred pages, and will not necessarily be
completed within one calendar year.
In 1965 a separate supplementary series of longer
papers was instituted, numbered serially for each
Department.
This paper is Vol. 25, No. 2, of the Geological
(Palaeontological) series. The abbreviated titles of
periodicals cited follow those of the World List of
Scientific Periodicals.
World List abbreviation :
Bull. Br. Mus. nat. Hist. (Geol.)
Trustees of the British Museum (Natural History), 1974
TRUSTEES OF
THE BRITISH MUSEUM (NATURAL HISTORY)
Issued 23 May, 1974 Price £2-85
THE TAXONOMY AND MORPHOLOGY OF
PUPPIGERUS CAMPERI (GRAY), AN EOCENE
SEA-TURTLE FROM NORTHERN EUROPE
By RICHARD THOMAS JONES MOODY
CONTENTS
Page
INTRODUCTION ........... 155
HISTORICAL REVIEW .......... 156
SYSTEMATIC DESCRIPTION ......... 161
SUMMARY AND CONCLUSIONS ........ 182
ACKNOWLEDGMENTS .......... 183
REFERENCES ........... 184
SYNOPSIS
Comparative studies show that the chelonians Eochelys longiceps (Owen), Lytoloma trigoniceps
(Owen) and Lytoloma camperi (Gray) are conspecific ; the valid name is Puppigerus camperi,
and a lectotype is designated. The species occurs in the Eocene of Belgium and England.
All known skeletal elements are described, certain ontogenetic trends are described and discussed,
and a few comments are made on the biology.
INTRODUCTION
IN THE collections of many Northern European museums are excellent examples of
the cheloniids Eochelys longiceps (Owen), Lytoloma trigoniceps (Owen) and Lytoloma
camperi (Gray). All three species are of Eocene age ; E. longiceps occurs in the
London Clay and Bracklesham Beds, L. trigoniceps in the Brackleshams only, and
L. camperi in the Bruxellian of Belgium.
The history of L. camperi began in 1781, when Buc'hoz (dec. 6, pi. 3, cent. 2)
figured an unnamed turtle carapace from the Sables de Bruxelles ; this specimen was
later to become one of the two syntypes of Emys camperi Gray (1831, p. 37). The
species Chelone longiceps and Chelone trigoniceps were erected by Owen in 1841 and
1850 respectively. The arguments that raged during this period as to the marine or
fresh- water affinities of Eocene turtles concerned (inter alia) C. longiceps and C.
trigoniceps but not E. camperi, which everyone accepted as a marsh turtle.
Cope (1871) erected the new genus Puppigerus, with C. longiceps and C. trigoniceps
among the included species, but he did not designate a type. Lydekker (18896)
designated C. longiceps as the type-species of Puppigerus, and, at the same time,
transferred the species to the genus Lytoloma. Lytoloma had also been erected by
Cope, in 1870, and is therefore a year older than Puppigerus. Lydekker's synonymy,
however, is only subjective ; and, in any case, the genus Lytoloma should have been
ignored, being based on two indeterminate species (Zangerl 1953 ; Moody 1968).
The same author (Lydekker 18890, &) discussed the morphology of the two British
species and decided that both were cheloniid turtles. Dollo (1923) claimed the same
for the species camperi, which too he referred to Puppigerus. The belief in the marine
156 PUPPIGERUS CAMPERI
affinities of all these species has persisted. The species Lytoloma longiceps [Chelone]
was made the type of the new genus Eochelys by Moody in 1968, who was then un-
aware that it was already the type of Puppigerus Cope. Eochelys thus became an
objective junior synonym of Puppigerus.
In recent years Dr E. Casier, Dr R. Zangerl and I have worked separately on the
morphology and taxonomy of the three species. Drs Zangerl and Casier have
recently made their material available to me so that the possibly synonymous species
could be compared on a wider basis. There is excellent associated material of
Puppigerus in the Institut Royal des Sciences Naturelles de Belgique, Brussels.
On the other hand, material from English localities in English museums consists
mainly of well-preserved but isolated skeletal remains ; nevertheless a great deal of
preparation and jig-saw type assembly carried out at the British Museum (Natural
History) has made it possible to compare the prepared material with the associated
remains in Brussels. The evidence undoubtedly indicates that the remains of the
three species are identical.
HISTORICAL REVIEW
EMYS CAMPERI Gray
The history of the Eocene turtles under revision began with the illustration of a
carapace by Buc'hoz in 1781. The specimen remained unnamed until 1784, when
Burtin claimed - obviously incorrectly - that it should be referred to the species
Testudo corticata, a name applied by Rondelet to the Recent Hawksbill Turtle
(Lepidochelys). Faujas St Fond (1799) agreed with this but, according to Dollo
(1923), stated that the specimen was similar to the Recent Green Turtle (Chelonia
mydas). Cuvier (1812) also thought it was a sea-turtle but, on reflection, described
and figured the carapace as one of the marsh turtles from the ' Environs de Bruxelles '
(1824, pi. 15, fig. 16 and pi. 13, fig. 8). Gray (1831) regarded Cuvier's description of
the turtles from Brussels as an indication of specific grouping and based a new species
Emys camperi on the two specimens figured by Cuvier. It is fortunate that these
syntypes have since proved conspecific, for Cuvier's illustrations are so inaccurate
that they could never be regarded as representative of a single species.
The syntypes of E. camperi were separated after 1830 ; the original carapace
illustrated by Buc'hoz remained in Brussels as I.R.S.N.B. I687/R.4; the other and
its counterpart were moved to Ghent to become G.M. 2250 and 2251 respectively.
The latter were figured and described by Poelman (1868, figs. 1-2), the description
confirming that the specimen had eight costal and nine neural plates. As it has not
been confirmed whether the last two specimens are still in existence, the Brussels
specimen is here designated as the lectotype of the species E. camperi. The belief
that E. camperi was a marsh turtle persisted until 1923, when Dollo assigned the
species to the marine genus Puppigerus Cope. Bergounioux (1933) disagreed with
Dollo's assignment of E. camperi to the genus Puppigerus and claimed that the species
would be more correctly referred to the American genus Lytoloma. He supported
Dollo's view, however, that E. camperi was a marine turtle. His reconstruction of the
animal bore little resemblance to the type material.
EOCENE SEA-TURTLE 157
CHELONE LONGICEPS Owen
Ten years after Gray's erection of the species E. camperi upon the forms figured
earlier by Cuvier, Owen (1841) described the species Chelone longiceps from the
London Clay of the Isle of Sheppey ; this form was destined to become the type
species of both Puppigerus Cope 1871 (see Lydekker 18896, p. 57) and Eochelys Moody
1968. C. longiceps was erected on skull and shell material correctly assigned to the
one species. However, over the next fifty years there was much discussion of the
possible synonymy of C. longiceps with Emys parkinsonii, a species erected by Gray
(1831) on remains figured by Parkinson (1811) and Cuvier (1824) from the Isle of
Sheppey.
Poelman (1868) decided that the two were synonymous and that E. parkinsonii
was the senior name, a lead followed by Winkler (1869). This conspecific evaluation
was in part correct, as one of the syntypes of E. parkinsonii (Parkinson 1811, fig. 2,
pi. 18) was a juvenile of 'longiceps' form, a fact noted by Owen (1842) in his descrip-
tion of C. longiceps. Since C. longiceps is here considered to be a subjective junior
synonym of E. camperi, the question arises as to the possible synonymy of E. camperi
and E. parkinsonii. Both are proposed on the same page of the same work (Gray
1831, p. 33), E. parkinsonii having line priority. The International Code of Zoo-
logical Nomenclature recommends (Recommendation 696 (12)) that the first-men-
tioned name should be used in such cases, all other things being equal. But all
other things are not equal. E. parkinsonii was based on a series of individuals which
do not all belong to the same species and from which no lectotype has been chosen,
and to use that name in preference to E. camperi for all the material described in the
present paper would only add to the confusion. It is therefore clear that the recom-
mendation does not apply in this instance and that the name E. camperi should be
retained.
The species C. longiceps and C. trigoniceps were regarded as valid by Lydekker,
who assigned them in 1889 to the genus Lytoloma ; this decision succeeded in
stabilizing a synonymy confused by Dollo, who had noted the similarity of the two
English species with Belgian forms referred variously to the genera Pachyrhynchus
Dollo, Erquelinnesia Dollo and Euclastes Cope between 1886 and 1888. The
synonymy of the various chelonians from the London Clay was discussed by Moody
(1968), when an account of the taxonomic confusion regarding these specimens was
given. As mentioned above, Moody erected the new genus Eochelys on the species
longiceps, unaware that that species was already the valid type of Puppigerus.
CHELONE TRIGONICEPS Owen
The synonymy of the species Chelone trigoniceps followed similar lines to that of
C. longiceps, the species being first described by Owen in 1849 and first figured, again
by Owen, in Dixon's Geology of Sussex (1850, pi. XIII, fig. 4). Lydekker (18896)
assigned the species to the genus Lytoloma and this has generally been accepted until
now.
158 PUPPIGERUS CAMPERI
Stratigraphical occurrence of Lytoloma
Sables de Wemmel Wemmelian U. Eocene
Barton Beds Bartoman U. Eocene
Sables de Bruxelles Bruxellian M. Eocene
Bracklesham Beds Lutetian M. Eocene
London Clay Lower Ypresian L. Eocene
The European material hitherto referred to Lytoloma includes the material housed
in the I.R.S.N.B., Brussels, under the names Lytoloma camperi, ' L. bruxelliensis' and
' L. wemelliensis' and in the British Museum (Natural History) under the names L.
longiceps, L. trigoniceps and L. crassicostatum (part). As indicated in the introduc-
tion to this paper the three Belgian species, L. longiceps and L. trigoniceps are doubt-
less all identical and the number of species in this genus is therefore only two.
The supposed differences between L. longiceps and L. trigoniceps were that L.
trigoniceps attained greater size and that its interorbital bar was relatively much
wider. The latter ' difference ' is without doubt the result of distortion and crushing ;
simple measurement (Table iB) shows that the relative width of the interorbital bar
is exactly the same in the two forms.
A summary of the measurements and indices recorded from the various species
(Tables I and 2) confirms the comparative studies undertaken. The tables also
show that L. camperi and L. longiceps are conspecific.
TABLE i
Measurements and indices recorded from skulls now referred to the species Puppigerus camperi
but formerly variously referred to the species Lytoloma longiceps and L. trigoniceps as well as to
L. camperi
A. Distance of internal nares from snout/total length of palate
distance of internal n
specimen nares from snout total length of palate — (as %)
n p P
mm mm
Lytoloma camperi
I.R.S.N.B. R.ig 23 52 44-2
I.R.S.N.B. R.i8 28 56 50-0
I.R.S.N.B. R.I7 45 87 51-7
I.R.S.N.B. R.i6 47 92 51-1
Lytoloma longiceps
H.M. 297 46 87 52-9
Spec. fig. Owen (1849) 46 86 53-6
B.M.(N.H.) R.2I&3 50 97* 51-5
Lytoloma trigoniceps No measurements available
Specimen referred by Lydekker (18896)
to L. crassicostatum
B.M.(N.H.) 38954 34 72 47-2
* Estimated.
EOCENE SEA-TURTLE
159
TABLE i (cont.)
B. Width of interorbital bar/length of orbit
width of
specimen interorbital bar
i
Lytoloma camperi
I.R.S.N.B. IG.8402
I.R.S.N.B. R.I9
Lytoloma longiceps
B.M.(N.H.) R.26I3
B.M.(N.H.) 38954
Lytoloma trigoniceps
B.M.(N.H.) 39771
mm
22
16
25
24
29
length of orbit
o
mm
25
18
27-5
26-5
32
%)
84-6
88-8
90-9
90-6
90-6
TABLE 2
Measurements (in mm) and indices recorded from shells now referred to the species
Puppigerus camperi
Neural plate
specimen
L. camperi
I.R.S.N.B. IG.9544
I.R.S.N.B. R.I3
I.R.S.N.B. 10.8632
I.R.S.N.B. IG.84o2/R.i7
I.R.S.N.B. R.i4
L. longiceps
B.M.(N.EL) 38951
B.M.(N.H.) 38950
specimen
L. camperi
I.R.S.N.B. IG.9544
I.R.S.N.B. R.I3
I.R.S.N.B. IG.8632
I.R.S.N.B. IG.8402/R.I7
L. longiceps
B.M.(N.H.) 38951
B.M.(N.H.) 38950
specimen
L. camperi
I.R.S.N.B. R.i4
I.R.S.N.B. R.i5
L. longiceps
B.M.(N.H.) 45902
B.M.(N.H.) 35721
B.M.(N.H.) 38951
ist 2nd 3rd 4th 5th 6th 7th 8th gth
33
30 33 33 28
28 22-5
18 9
34
17
30 29 29 24
17 15 18 14
24 21
12 II
15 15
8 5
32
29 31
28 30 23
26 21
13 ii
24
22
26 24 25 23
I7-5 19 20 17
21-5 19-5
17 16
17
13
Neural shield measurements
2nd 3rd
A A
4th
A
L
^ r *»
W L W
L W
69
62
72 65 71
68 58 62
75 65
61 61
34
66
49 34 51
72
34 45
52
44
62 50 63
56 41 51-5
58 56
45 48
Plastral index A
axillo-inguinal
width
£ width of
plastron
- (as %;
a
w
87
105
82-9
92
104
88-5
52
64
74
80
70 +
80
70
95
73'6
i6o PUPPIGERUS CAMPER I
TABLE 2 (cont.)
Plastral index B
length from hyo-
axillo-inguinal hyposuture to
specimen width xiphi tip - (as %)
a h
L. camper i
I.R.S.N.B. R.I5 92 136 67-6
I.R.S.N.B. R.I4 87 114 76-3
L. longiceps
B.M.(N.H.) 38951 70 99 70-7
B.M.(N.H.) 25608 53 71 75-7
B.M.(N.H.) 38950 55 73* 75'3
B.M.(N.H.) R.I9I7 43 64 67-2
B.M.JN.H.) 35721 61 89 68-5
Xiphiplastral index
length of length of
specimen xiphiplastron plastron - (as %)
x I
L. camperi
I.R.S.N.B. R.I5 87 266 32-7
I.R.S.N.B. R.i4 73 218 33-5
L. longiceps
B.M.(N.H.) 38951 64 201 31-8
B.M.JN.H.) 25608 45 138 32-6
B.M.(N.H.) 35721 54 185 29-2
B.M.JN.H.) R.3964 48 156 30-7
L. camperi
I R.S.N.B. 10.8632 40 127 31-5
*Estimated.
The obvious synonymy between L. camperi and L. longiceps is shown by a com-
parison of the skull I.R.S.N.B. IG.84O2/R.I7 (Figs. 2-5, PI. 2) with either the type
skull of C. longiceps figured by Owen (1849), which is missing presumed lost, or the
skull H.M.297, also figured by Owen in 1849. Other comparisons can be made
between shell and limb remains, and the similarity is confirmed by a comparison of
the plastra of I.R.S.N.B. 10.8632 and B.M.(N.H.) 38951 (PI. 8).
The belief that the three forms are conspecific renders it necessary to comment
briefly on the synonymy. As mentioned above, the species longiceps was made the
type of the new genus Eochelys by Moody (1968), who thought that the generic
names Lytoloma and Puppigerus were both unsuitable. But the realization that
Puppigerus is an objective senior synonym of Eochelys, and the placing of camperi
and longiceps in subjective synonymy, together necessitate that all this material
should now be called Puppigerus camperi.
EOCENE SEA-TURTLE 161
This species is described in detail below.
A comparative table (p. 162) of the families Plesiochelyidae, Thalassemydidae,
Toxochelyidae and Cheloniidae shows that Puppigerus is not a thalassemydid, as
had been suggested by Cuvier (1824, writing about the material on which Gray later
based E. camperi}. Rather does it confirm Moody's belief (1968) that Puppigerus
[Eochelys] is a cheloniid. In the same work Moody indicated that most British
Eocene marine turtles were not toxochelyids.
SYSTEMATIC DESCRIPTION
Family CHELONIIDAE
Subfamily EOCHELYINAE Moody 1968
EMENDED DIAGNOSIS. Skull more or less triangular as seen from above ; dermal
and epidermal elements few and regularly arranged (like Cheloniinae, unlike Caret-
tinae) . External naris faces forwards and/or upwards ; orbit faces slightly forwards
and outwards, with frontal forming part of its rim. Secondary palate may be
present, bounded by low, steep cutting edges ; position of internal naris extremely
variable. Cervical vertebrae short and stout, articulating as in Recent members of
the family. Limbs intermediate in structure between toxochelyids and Recent
cheloniids, although humeral : femoral ratio is fully cheloniid. Carapace moderately
arched, thickness of plates variable ; neurals eight or nine in number and generally
unkeeled. Plastron cruciform, variously ossified, epiplastra wedge-shaped or slightly
rounded. No sutural contact between carapace and plastron.
Subfamily includes genera Puppigerus Cope (objective junior synonym Eochelys
Moody), Argillochelys Lydekker and Eochelone Dollo.
Genus PUPPIGERUS Cope 1871
TYPE-SPECIES. Chelone longiceps Owen 1841 by subsequent designation (Lydekker
18896).
EMENDED DIAGNOSIS. Snout of moderate length in juveniles but very elongate,
pinched and narrow in the adults of certain species. Occipital shield present in
epidermal mosaic. Extensive secondary palate, with or without shallow median
sulcus, large area occupied by palatine ; premaxilla and vomer narrow and elongate.
Internal narial opening narrow or quite large ; area in front of opening flat, without
swelling ridges. Ectopterygoid processes fairly small, anterior pterygoid area nar-
rower than in Argillochelys. Basioccipital depression shallow and smooth. Mandible
with elongate symphysis, more than one-third the length of the mandible itself ;
dorsal surface of symphysial area very flat or gently concave. Vertebral column
as in Recent cheloniids. Carapace more rounded than in Argillochelys ; eight or
nine neural plates, each slightly longer than broad and with antero-lateral facets
much shorter than postero-lateral facets ; vertebral scutes almost square ; fontanelles
may be present between costal and peripheral plates in adult specimens. Plastron
*
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EOCENE SEA-TURTLE 163
extensively ossified, with central fontanelle (if present) of variable size ; epiplastra
wedge-shaped as in Eretmochelys and Catapleura, hyo-hypoplastral suture extensive,
xiphiplastra short and broad. Texture of bone surface smooth and without pro-
nounced pattern visible in Argillochelys.
Puppigerus camperi (Gray) [Emys]
1784 Testudo corticata (Rondelet) Burtin, p. 93, pi. 5.
1799 'Tortue Franche' (Chelonia mydas) Faujas St Fond, p. 60.
1824 Emydes de Bruxelles : Cuvier, p. 236, pi. 13, fig. 8.
1824 Emydes de Sheppey : Cuvier, p. 234, pi. 15, fig. 7.
1831 Emys camperi Gray, p. 33. Based upon Cuvier's figures of 1824.
1831 Emys parkinsonii Gray, p. 33.
1837 Emys cuvieri Galeotti, p. 45.
1841 Chelone longiceps Owen, p. 572.
1842 Chelone longiceps Owen : Owen, pp. 162, 172.
1849 Chelone longiceps Owen : Owen & Bell, p. 16, pis. 3-5.
1849 Chelone trigoniceps Owen & Bell, p. 31.
1849 Chelone longiceps Owen : Owen, p. 16, pis. 12-13.
1849 Chelone trigoniceps Owen : Owen, p. 31, pi. 25.
1849 Chelone auticeps Owen, pi. 25.
1850 Chelone trigoniceps Owen : Owen, p. 218, pi. 13.
1854 Chelone longiceps Owen : Owen, p. 72.
1868 Emys camperi Gray : Poelman, p. 105, pis. 1-2.
1868 Emys parkinsonii Gray : Poelman, p. in, pi. 3.
1869 Emys camperi Gray : Winkler, p. 129, pis. 26-28.
1869 Emys parkinsonii Gray : Winkler, pis. 24, 25.
1870 Puppigerus longiceps (Owen) Cope, p. 235.
1886 Pachyrhynchus longiceps (Owen) Dollo, p. 138.
1886 Pachyrhynchus trigoniceps (Owen) Dollo, p. 138.
18896 Lytoloma longiceps (Owen) Lydekker, p. 57.
18896 Lytoloma trigoniceps (Owen) Lydekker, p. 53.
18896 Lytoloma crassicostatum (Owen) (part) Lydekker.
1909 Emys camperi Dollo, p. in.
1923 Puppigerus camperi (Gray) Dollo, p. 416.
1933 Lytoloma camperi (Gray) Bergounioux, pp. 1-13, figs. 1-4.
1968 Eochelys longiceps (Owen) Moody, p. 131.
SYNTYPES. I.R.S.N.B. 1687 - Lectotype, designated herewith.
G.M. 2250, 2251 - Paralectotypes. (As yet no confirmation has been
received that these specimens, figured by Poelman (1868), are still in Ghent.)
DESCRIPTION OF LECTOTYPE, I.R.S.N.B. 1687 (Fig. i). Incomplete carapace,
lacking most of the peripheral plates ; specimen very fragmentary on left-hand side ;
nuchal incomplete ; nine neural and eight costal plates. On list of types housed in
I.R.S.N.B. It is, without doubt, closer to the specimen figured by Cuvier (pi. 13,
fig. 8) than the other syntype and is therefore designated herewith as the lectotype
of Puppigerus camperi.
I64
PUPPIGERUS CAMPERI
5cm
FIG. i. Puppigerus camperi (Gray). Lectotype (I.R.S.N.B. 1687/11.4). From above,
drawn from a photograph.
REFERRED SPECIMENS.
I.R.S.N.B. 1663, 1664, 1665, 1666, 1667, 1668, 1669, 1684, 1685, 1686, I687/R.4,
1689, R.5, R.I3, R.I4, R.i6, IG.8402/R.I7, R.i8, R.ig
G.M. 2250, 2251, 2252
B.M.(N.H.) 25609, 28853, 30526, 35608, 35689, 37207, 372H, 38950, 38954, 38959,
39763, 39771, 44092, R-I025, R.I425, R.I475, R.i48i, R.2i63, R.8553
G.S.M. 57266, 57267, 92297, 92298
Hunterian Collection, R.C.S. H.M.297
Sedgwick Museum, Cambridge. C. 20924, 20926, 20930, 20933
Maidstone Museum (M.M.) (G.S.M. TN). 9551, 9552, 9554, 9957
Also belonging to this species are two very poor fragmentary mandibles in the
I.R.S.N.B. labelled, in Dollo's handwriting, ' Lytoloma bruxelliensis' and ' Lytoloma
wemelliensis' . These are presumably the specimens upon which, in 1909, Dollo
based those two names (they should in fact have been L. bruxelliense and L. wemel-
liense, the Greek noun AOJJLKX being of the neuter gender). The names, however,
were given without adequate indication and are certainly nomina nuda ; since they
cannot be formally connected with the specimens they are not included in the
synonymy.
EOCENE SEA-TURTLE 165
OCCURRENCE OF SPECIES.
Sables de Wemmel - Wemmelian - Upper Eocene. Belgium. (See Curry 1966.)
Sables de Bruxelles - Bruxellian - Middle Eocene. Belgium.
Bracklesham Beds - Lutetian to Auversian - Middle Eocene. England.
London Clay - Lower Ypresian - Lower Eocene. England.
The specimens referred to this species range widely in both size and state of preser-
vation. The material studied includes numerous skulls, vertebrae, limb and girdle
elements and shells, together with a few excellent associated skeletons (PL i). The
smallest known specimens are G.S.M. 57266 and B.M.(N.H.) 28853, of which the
last has been prepared with the air-abrasive and has yielded a tremendous amount of
skeletal material. The largest specimens are housed in the Belgian collections and
reach a maximum length of 350 ± mm. From such a range of material the following
specific diagnosis is drawn.
EMENDED DIAGNOSIS OF P. camperi. Snout region elongate in adult, tapering
anteriorly to a point ; in side-view, premaxilla plus maxilla much longer than jugal
plus quadrato-jugal. Extensive secondary palate, with narrow internal narial
opening situated (in adult) in third quarter of ventral skull length ; very long vomer
and premaxilla and short rounded palatine ; palatal surface pitted. Palatine ex-
tends backwards to form a shelf lying ventral to the pterygoid and small ectoptery-
goid process ; pterygoid bar narrow. Basioccipital depression fairly deep, without
rugose surface. Braincase basically cheloniid, but with distinct specific* characters
(see description). Carapace of adult completely ossified, broadly cordiform and
gently arched ; nine neurals and two pygals ; juvenile forms with costo-peripheral
fontanelles. Plastron with small to medium-sized central fontanelle ; epiplastra
wedge-shaped as in Catapleura ; entoplastron T-shaped ; xiphiplastron short and
wide. Plastral index 70-85.
DESCRIPTION OF MATERIAL. There are many excellent skulls amongst the specimens
listed above, and the following description is drawn from I.R.S.N.B. R.I4, R.J-5,
R.i6, IG.8402/R.I7, R.i8 & R.ig ; B.M.(N.H.) 38954 & R.26i3 ; and H.M.297.
The previously noted similarity between the adult skulls formerly ascribed to the
respective species Emys camperi (PI. 2) and Chelone longiceps (H.M.297), *s also aP~
parent in the juvenile specimens I.R.S.N.B. R.ig (PI. 3A) and B.M.(N.H.) R.I475,
in which the snout region is much shorter. The progressive pinching in of the snout
as seen in dorsal view is an outstanding ontogenetic trend. The snout of the
juvenile is very similar in shape to that of Chelone crassicostata ; the snout of the
adult, however, is pinched below the orbits and tapers anteriorly to a more pro-
nounced and acutely pointed beak, as is shown particularly well in I.R.S.N.B.
IG.8402/R.I7 (Figs. 2-5). This pinching in of the snout is demonstrated by a
growth series of P. camperi skulls (R.ig, R.i8, R.i6 - see Plate 3) ; this same series
also shows the progressive increase in the jugal index from 33-3 to 41-2 (Table 3).
It is noticeable that despite this gradual increase in the jugal and quadratojugal
indices within the P. camperi series, the premaxilla-maxillary length is still pro-
portionally much greater than in the other eochelyines.
166
PUPPIGERUS CAMPERI
EOCENE SEA-TURTLE
.par
po
167
fr
Pfr
FIG. 4. Puppigerus camperi (Gray). Reconstruction of skull x i, based on
I.R.S.N.B. IG.8402/R.I7. From right side. Abbreviations as on p. 184.
vesK
soc
par.
fr.
pfr.
fn.
exo-
pmx.
FIG. 5. Puppigerus camperi (Gray). Reconstruction of skull x i, based on I.R.S.N.B.
IG.84O2/R.I7. Parasagittal section close to midline to show braincase. Abbreviations
as on p. 184.
Table 4 shows that the internal narial opening is retreating backwards over the
ventral surface of the skull as the animal grows. The premaxilla and vomer are
elongate in this species, the vomer narrowing anteriorly but expanding slightly in the
area of contact with the maxilla and palatine. The palatine is shorter and more
rounded than in other species ; it often expands medially and posteriorly to reduce
the front part of the internal narial opening to a narrow slit (shown well in I.R.S.N.B.
168
PUPPIGERUS CAMPERI
TABLE 3
Measurements (in mm) and indices recorded for the bones of the outside edge of the skulls of
three eochelyine species
total length of
premaxilla +
maxilla
specimen
Puppigerus camperi
I.R.S.N.B. R.IQ
I.R.S.N.B. R.i8
I.R.S.N.B. R.I7
I.R.S.N.B. R.i6
Puppigerus crassicostatus
B.M.(N.H.) 372isa
B.M.JN.H.) 25610
B.M.JN.H.) 35696
B.M.(N.H.) R-3Q64
Argillochelys cuneiceps
B.M.(N.H.) 41636
27
33
46
39
33
32
length of
jugal
j
— (as
9
il
20
22
23
20
20
19
33
33-3
33-3
43-5
60-6
62-5
80-5
length of
quadrato-
jugal
7
5
8
13
8
8
16
— (as
m
25-9
15-1
17-3
25-5
20-5
24-2
39-o
TABLE 4
Measurements (in mm) to illustrate the variation in the position of the internal narial openings
with size in Puppigerus camperi, and a comparison with other Eocene forms
specimen
Puppigerus camperi
I.R.S.N.B. R.ig
I.R.S.N.B. R.i8
B.M.(N.H.) 38954
I.R.S.N.B. IG.8402/R.I7
H.M. 297
I.R.S.N.B. R.i6
Puppigerus crassicostatus
B.M.(N.H.) 38955
B.M.(N.EL) 372i3a
Argillochelys cuneiceps
B.M.(N.H.) 41636
distance of quarter
length of narial opening , in which
skull below from tip of snout - (as %) choanae sited
/ d l
52 23 44-2 2
56 28 50-0 2-3
72 36 5°'° 2-3
87 45 5i-7 3
87 46 52-9 3
92 47 51-1 3
56 22 39-3 2
64 26 40-6 2
C. 91 26-5 29-I 1-2
R.i6, Fig. 6) and to form a shelf ventral to the ectopterygoid process. The latter is
not as pronounced as in either C. crassicostata or Argillochelys. The pterygoid bar is
narrow in P. camperi and does not expand anteriorly to any great extent (Fig. 6).
Posteriorly the pterygoid borders the fairly shallow, smooth, basisphenoid/basi-
occipital depression ; the quadrate ramus bears a deep groove running along its
ventral surface, its antero-lateral margin curving downwards towards the
basioccipital.
EOCENE SEA-TURTLE
169
B
5Omm
5Omm
FIG. 6. Puppigerus camperi (Gray) . Skulls, from below. A. I.R.S.N.B. R. 19
B. I.R.S.N.B. R.i8 C. I.R.S.N.B. R.i6
Peculiar to the skull I.R.S.N.B. R.IQ is the presence of a mid-line foramen, just
behind the fronto-parietal suture (PI. 3 A, Fig. 7). This foramen is a definite opening
and is not to be confused with the parasitic lesions that so often occur in London
Clay specimens. The presence of this parietal foramen was first noted by Edinger
(1933) and was later mentioned by Zangerl (1957) in a comparison with Testudo
denticulata. The foramen is circular and has an anteroposterior diameter of 2-2 mm
(Table 5).
Testudo denticulata
R.Z. 612
Puppigerus camperi
I.R.S.N.B. R.ig
13
TABLE 5
Comparative table
distance of
parietal foramen
from tip of snout
length of skull
42
65
(incomplete)
c. 19-5
35
diameter of
parietal foramen
mm
0-9
2-2
170
PUPPIGERUS CAMPERI
B
10mm
FIG. 7. Reconstructions of skulls of juvenile chelonians, from above, to show parietal
foramen. A. Puppigerus camperi (based on I.R.S.N.B. R.ig). B. Testudo denticulate
(based on R.Z. 612). C. Puppigerus camperi (based on I.R.S.N.B. R.i8).
Braincase
The braincase of P. camperi is known from the sectioned skull of the Belgian
specimen I.R.S.N.B. IG.84O2/R.I7 (Fig. 5). The bones of the side-wall of the
braincase are the pterygoid, parietal, prootic, supraoccipital, opisthotic and ex-
occipital. The bones of the floor are the basisphenoid, the anterior part of which, the
rostrum basisphenoidale, is underlain by the pterygoid, and the basioccipital, which
is encroached upon by the exoccipital just anterior to the foramen magnum.
The pterygoid extends upwards from beneath the basisphenoid to form the lower
antero-lateral portion of the braincase, the crista pterygoidea. The sulcus caver-
nosus is well developed between the pterygoid and the rostrum basisphenoidale,
much as in Chelonia mydas. Postero-laterally the pterygoid forms part of the
border of the large foramen nervi trigemini. Laterally the pterygoid is narrower
than in most other cheloniids, but not as narrow as in Argillochelys. The vertical
EOCENE SEA-TURTLE
171
pterygoid process fuses with the basisphenoid in the sella turcica region to form a
wide shelf in front of and to the side of the dorsum sellae, thus providing a canal
between the two bones for the internal carotid. The internal carotid canal therefore
joins the sulcus cavernosus well forward of the foramen nervi trigemini ; in Chelonia
mydas the canalis cavernosus is behind this foramen.
Part of the anterior border of the foramen nervi trigemini is formed by the ventral
parietal element ; the suture between the parietal and the processus pterygoideus
beneath it terminates posteriorly at that foramen. In I.R.S.N.B. IG. 8402/1^.17 the
vertical parietal element is apparently pierced by a second large 'foramen' (Fig. 5).
This ' foramen ' is much reduced on the opposite side of the cavum cranii and, as the
bone in that region is translucent in other sectioned skulls, it is probably due to
damage and/or subsequent preparation. The vertical prootic component is reduced
in lateral view because of the large foramen nervi trigemini anteriorly and the vesti-
bulum posteriorly (Fig. 5) ; the internal surface area of the prootic is reduced in all
eochelyines which have been sectioned, but it is possible that larger specimens were
more heavily ossified.
Incomplete ossification may also be an important factor in reducing the internal
dimensions of the opisthotic (Fig. 5), which is relatively smaller than in Chelonia
mydas (Goodrich 1930, fig. 420) ; it forms an incomplete bar between the vestibulum
and the foramen jugulare.
The exoccipital forms the posterior portion of the braincase wall and the posterior
border of the foramen jugulare anterius ; it is pierced by the foramen for the twelfth
nerve.
The dorsal portions of the basisphenoid and basioccipital form the floor of the
braincase. The basisphenoid extends anteriorly over the suture of the pterygoid to
the posterior area of the palatine ; its anterior portion forms the rostrum basi-
sphenoidale, the complete structure of which is unknown because of damage by
sectioning. The rostrum appears to have been elongate as in the Cheloniidae but the
foramen arteriae cerebralis is much nearer to the dorsum sellae than in Recent forms
and is connected ventrally with the pronounced sulcus cavernosus. The sella turcica
is overhung by the dorsum sellae. The foramina of the nervus vidianus and nervus
abducens are very small, but the processus clinoideus is quite large. Behind the
dorsum sellae and the processus clinoideus the basisphenoid is a concave plate ; this
plate is divided by a small ridge, the crista basisphenoidalis, which is less pronounced
than in the toxochelyids or Recent cheloniids.
The basioccipital too is concave anteriorly, but is encroached upon posteriorly by
the exoccipital ; only in the toxochelyids does the basioccipital extend backwards
dorsally to the occipital condyle. The basis tuberculi basalis and crista basi-
occipitalis are reduced in P. camperi. The basioccipital is smooth on its dorsal
surface, the numerous ridges typical of Toxochelys and Chelonia being absent.
The cavum labyrinthicum and cavum acustico- jugulare of the eochelyines are
best known from species other than P. camperi. Both are very similar to those of
Recent cheloniids and of the genus Stegochelys as described by Parsons & Williams
(1961 p. 80). This is also true of the columella of Puppigerus camperi (known from
the specimen B.M.(N.H.) 25599).
13*
172
PUPPIGERUS CAMPERI
Endocranial cast
The endocranial cast (Fig. 8) of P. camperi taken from I.R.S.N.B. IG.8402/R.I7
reflects very little of the actual brain morphology. The information provided by
such casts is of general interest only and, in the main, simply illustrates the principal
flexures of the brain (Fig. 8). This lack of detail has been noted previously by
Zangerl (1960) and Gaffney (1968). Only in the massively constructed braincase of
Corsochelys haliniches (Zangerl 1960) are the subdivisions of the brain partially
reflected in the endocranial cast.
B
FIG. 8. Puppigerus camperi (Gray). Endocranial cast taken from sectioned skull,
I.R.S.N.B. 10.8402 x f. A. From left side. B. From above, pbf - principal brain
flexure.
Lower jaw
The lower jaw of P. camperi (Fig. 9 ; PI. 2C) is well known from numerous Bruxel-
lian and Bartonian specimens and from one excellent London Clay specimen,
B.M.(N.H.) R.8553. The masticatory surface of the jaw is typically almost flat,
but does show a very slight concavity in both the anteroposterior and transverse
directions. The length of the symphysis is approximately one-half that of the
mandibular ramus and the dorsal symphysial surface is always longer than the ventral.
The ventral surface has a faint median ridge and a shallow depression posteriorly.
The elongation of the symphysial region of the lower jaw is a close reflection of the
elongate nature of the secondary palate.
Posterior to the mandibular symphyses of specimens I.R.S.N.B. R.I5 and
I.R.S.N.B. IG.84O2/R.I7 is evidence of thehyoid apparatus (Fig. 10 ; Pis. i & 2B) ;
in the case of the latter specimen it is to be seen on the nodule bearing the carapace.
In IG.8402/R.I7 the copula is incompletely ossified and shaped like a tuning-fork ;
EOCENE SEA-TURTLE
173
in R.I 5 it is more heavily ossified, the body being complete and shield-like in appear-
ance. The first cerato-branchial arches are also present ; these are relatively
common as skeletal fragments within fossils of this group.
B
--art
--art
FIG. 9. Puppigerus camperi (Gray) . Lower jaw x £. A. From above.
B. From below. C. From behind. D. From left side. Abbreviations as on p. 184.
A
2cm
FIG. 10. Puppigerus camperi (Gray). Hyoid apparatus. A. Mandible and copula, from
below (I.R.S.N.B. 10.8402). B. Mandible, copula and first ceratobranchial arch, from
below (I.R.S.N.B. R.IS).
174 PUPPIGERUS CAMPER I
Cervical vertebrae
The cervical vertebrae of P. camperi are known fully from the prepared specimen
B.M.(N.H.) 28853 (Pis- 4-5) and, in lesser degrees, from the specimens I.R.S.N.B.
R.I4 and R.I5 ; Plates i and 6 show the great similarity between the
cervical vertebrae of Puppigerus and those of Argillochelys. As stated previously,
they are also very similar to those of all other marine turtles. The immediate dif-
ference between the two vertebral series is in the articulation pattern for, whereas
that of P. camperi B.M.(N.H.) 28853 is (2(3(4)5)6/7)8), that of Argillochelys cuneiceps
S.M.C. 20937 is (2(3(4)5)6)7)8). The former pattern is characteristic of the advanced
sea-turtles (Williams 1950). Other than this, the main differences between the two
series are concerned with the depth of the hypapophysial keels and the position of
certain zygapophysial surfaces.
In P. camperi the hypapophysial keels are exceptionally well-developed on the first
five vertebrae and remain as significant features through to the last (eighth) cervical.
In Argillochelys the keels are again present but, as in Corsochelys haliniches (Zangerl
1960) and Dermochelys (Volker 1913, pi. 31), are pronounced developments of only
the second, third and fourth cervicals. In Dermochelys the keels acted as areas of
attachment for sheaths of cartilage, and Zangerl postulated a similar role for those of
Corsochelys. The actual function of the cartilaginous sheaths was unexplained,
except that it was to be regarded as an advanced marine specialization ; my own
investigation into this question has resulted in no firm conclusions.
Variation in the zygapophysial surfaces is evident in the second, third and fourth
vertebrae of the two series (Pis. 4 & 6) . In Puppigerus camperi (PI. 4) the zygapophy-
sial surfaces are more horizontal than those of Argillochelys (PI. 6). This difference
would suggest greater lateral movement within the forward neck region of P. camperi,
which would certainly agree with the inshore mode of life postulated for this form
(Moody 1970) . The increased tilt of the surfaces in A rgillochelys would restrict lateral
movement but permit greater vertical movement. Once again comparison is made
with the form Corsochelys haliniches (Zangerl 1960, pi. 32), in which the surfaces are
also tilted vertically. Thus the variations in depth of the hypapophysial keel and
in tilt of the zygapophysial surfaces may be specializations related to particular
environments and modes of life. The cervicals of P. camperi show similarities with
Corsochelys and Caretta (Zangerl 1960, pis. 31-33) ; the position of the neurocentral
suture, however, is more like that of Corsochelys.
Dorsal vertebrae
The dorsal vertebrae of P. camperi have been prepared, together with the central
part of the carapace, from the same specimen B.M.(N.H.) 28853 (PI. 5). This speci-
men is a juvenile, so that the dorsal vertebrae are not completely fused together ; a
ventral view shows large spaces between the first five centra. Spaces are also present
between the rib heads and the synapophyses. All these spaces were filled with
cartilage during the early stages of growth. Each dorsal vertebra (except the first)
is fused to the corresponding neural plate ; the first, which lies beneath the nuchal
EOCENE SEA-TURTLE
175
plate, is somewhat similar to the eighth cervical in that it has a much reduced centrum
and an elongate neural arch. The centrum of the first dorsal is procoelous to receive
the condyle of the eighth cervical ; and the whole vertebra is tilted forwards to an
angle of some 45 degrees, the posterior portion of the neural arch touching the ventral
surface of the nuchal plate. After the first, the centra of the dorsal vertebrae are
much reduced, laterally compressed and constricted in the centre to give a waisted
appearance. The ends of the centra of this immature specimen are flat. The dorsal
blade formed by the fusion of the neural arches is very thin, although it does expand
anteriorly with the rest of each arch to form the dorsal part of the synapophyses ;
the ventral portions of the latter are formed by the underlying centra. The neural
arches are intercentral in position, each being extended forwards ; the spinal nerve
openings occur above the middle of each centrum. Hoffstetter & Gasc (1969)
described the composition of the same region in Pseudemys ornata, which appears to
be very similar.
The ribs arise intervertebrally, as in all turtles, and they arch upwards to fuse
with the carapace. The tunnel formed between the vertebrae, ribs and costal plates
is in life occupied by epaxial musculature (Vallois 1922, fig. 16) ; it is well developed
as far back as the third rib, but is then reduced to a very small opening. The first
rib is reduced and fused distally with the second (as is typical of sea-turtles) . The
notch between the articular facets of the two ribs is similar to that of the Cheloniidae.
Sacral and caudal vertebrae
The sacral vertebrae of P. camperi are known from the specimen H.M.297 ; another
specimen, B.M.(N.H.) R.i48o (Fig. n), has similar sacrals but is without a skull and
cannot be determined with certainty. The sacrum of the latter specimen is made up
of two sacral vertebrae and a modified first caudal, all ankylosed together. The
centrum of the first sacral is strongly procoelous whilst the first caudal has a large
A
B
2cm
FIG. ii. Puppigerus camperi (Gray). Sacrum (B.M.(N.H.) R.i48o). Specimen referred
by Lydekker to Lytoloma trigoniceps (Owen). A. From above. B. From below.
176 PUPPIGERUS CAMPERI
condyle posteriorly ; radiography, however, has failed to show whether all these
vertebrae are procoelous. Sharp neural crests are visible and the first caudal bears
large postzygapophyses. The first sacral rib is greatly expanded laterally and in
side-view is thickened anteriorly. The second rib, although smaller, is also expanded.
In H.2Q7 the first sacral vertebra and rib are missing, but the other two vertebrae
and ribs are very similar to those of B.M.(N.H.) R.i48o. In both specimens the
caudal rib is expanded anteriorly and curved distally.
Two caudal vertebrae remain attached to the sacrum of H.297, but the only other
articulated caudal vertebrae attributable to this species are three vertebrae of speci-
men I.R.S.N.B. R.i-4 (PI. lA), the centra of which are similar to those of the dorsal
vertebrae ; they are 22 mm, 16 mm and 13 mm long respectively.
Girdles and limbs
The girdle and limb material prepared from the immature specimen B.M.(N.H.)
28853 (PI. 5) shows clearly the peculiar mixture of cheloniid and toxochelyid charac-
ters noted for the Eochelyinae by Moody (1968). This is shown even better by dis-
articulated elements referred to mature specimens of the same species.
The pectoral girdle and fore limb definitely tend towards the cheloniid condition.
The scapula (PI. 56) has a pronounced 'neck region' between the glenoidal and cora-
coidal facets and the base of the bifurcation, while the coracoid (PI. 5E) is much
longer than the dorsal process of the scapula. A table (Table 6) of the measurements
and indices of the shoulder girdle in the Toxochelyidae, Eochelyinae and Recent
Cheloniidae shows clearly the direct affinities between the latter two groups.
TABLE 6
Shoulder girdle measurement and indices of the Toxochelyidae, Eochelyinae and
Recent Cheloniidae
Vb Vc Vd
specimen Va Vb ~a (as %) Vc ~a (as %) Vd ~a (as %)
*Toxochelys latimeris
Y.P.M. 3602 26 13-5 51-9 34-5 132-7
C.N.H.M. PR.I23 940 48-0 51-0 122-0 129-7 J37 T45'7
Puppigerus camperi
B.M.(N.H.) 28853 26 15 57-7 29 ni'5 41 I57'7
*Lepidochelys kempi
C.N.H.M. 31334 76 25-5 46-7 90 118-4 II8 I42'5
B.M.(N.H.) 1940.3.13.1 40 18-5 46-2 47 117-5 57 162-5
*Chelonia my das
C.N.H.M. 22066 153 89 58-1 183 119-6 304 198-7
Va = length of ventral prong of scapular fork from tip of process to edge across neck of scapula.
Vb = length of scapular neck from base of fork to ridge dividing glenoidal facet from carocoid suture
face.
Vc = length of dorsal prong of scapular fork from tip of process to edge across neck of scapula.
Vd = maximum length of coracoid.
*After Zangerl (1953, tab. 5).
EOCENE SEA-TURTLE
177
The humerus of P. camperi (PL 5D) has a straighter shaft than that of the toxo-
chelyids and a more pronounced radial process, which latter is also situated further
down the shaft. The humerus is similar to that of Eochelone brabantica and other
cheloniids such as ' Chelone' vanbenedeni Smets 1886, Corsochelys haliniches Zangerl
1960 and Desmatochelys lowi (Zangerl & Sloane 1960).
The radius and ulna are known only from a few specimens and are usually un-
associated. The two bones lie close to each other in I.R.S.N.B. R.I5 (PI. iB), and
measure 41 mm and 32 mm respectively.
A comparison with the fore limb bones of the Recent Cheloniidae and the Toxo-
chelyidae (Table 7) brings out two interesting points. First, as in the Recent
cheloniids, the radius of Puppigerus is much larger than the ulna ; secondly, those
two bones are proportionally shorter in relation to the humerus than those of either
the Recent Cheloniidae or the Toxochelyidae.
TABLE 7
Measurements (in mm) and indices of the fore limb bones of the Eochelyinae, Recent Cheloniidae
and Toxochelyidae
EOCHELYINAE
Puppigerus camperi
I.R.S.N.B. R.i5
RECENT CHELONIIDAE
*Eretmochelys imbricata
C.N.H.M. 31009 (sub adult)
*Chelonia mydas
C.N.H.M. 22066 (adult)
TOXOCHELYIDAE
*Toxochelys latimeris
Y.P.M. 3602
C.N.H.M. PR.I23
*Toxochelys moorevillensis
C.N.H.M. PR.I36
length of
humerus
h
74
79
213
37
130
length of
radius
r
48
140
Ti (as %)
55-4
60-7
length of
ulna
u
+ 120
65
60
43-2
51-6
50-0
50-0
* After Zangerl (1953, tab. 8, p. 177).
Bones of the pelvic girdle and hind limb are much more commonly preserved than
those of the pectoral girdle and fore limb. The bones prepared from B.M.(N.H.)
28853 (PL 5) allow a direct statistical comparison to be made with other turtles, and
the index of 23-2 recorded for the area of the eochelyine ischium against the area of
the pubis falls between the 14-9 and 46-3 recorded for Eretmochelys and Toxochelys
respectively (Table 8). The development of a pronounced posterior spur on the
ischium (PL lA ; Fig. 12) distinguishes the girdle of this species from those of
the Recent Cheloniidae. The general morphology of the pelvic girdle of P. camperi
is, as in other eochelyines, intermediate between the toxochelyid and cheloniid
conditions.
i78
PUPPIGERUS CAMPERI
FIG. 12. Chelonian pelvic girdles. A. Chelydra. B. Toxochelys. C. Puppigerus.
D. Eretmochelys. A, B and D from Zangerl, 1953, p. 163.
TABLE 8
Measurements (in mm2) and indices of surface areas of ischium and pubis in Eretmochelys,
Puppigerus and Toxochelys
* Eretmochelys imbricata
C.N.H.M. 22352
Puppigerus camperi
B.M.(N.H.) 28853
*Toxochelys moorevillensis
C.N.H.M. P.273QI
* After Zangerl (1953, tab. 6, p. 164).
area of
pubis
P
2217
2442
2308
area of
ischium
t
566
1069
• (as %)
14-9
23-2
Several bones of the pelvic girdle and hind limb are present in the specimen
I.R.S.N.B. R.I5 (PI. iB), in which the femur and tibia may be measured and
compared with the humerus, radius and ulna (Table 7). The femur is approximately
50 mm in length and, although morphologically identical to that of the Toxochelyi-
dae, is shorter in relation to the humerus than that of even the Recent Cheloniidae.
The index femur/humerus is 67-5, as against 70-9 for Eretmochelys and 75-1 for Chelonia
(see Zangerl 1953, p. 177, tab. 8). The index tibia/humerus is 66-3 and is similar
to those recorded for both Cheloniidae and Toxochelyidae. Partial pelves and hind
limbs from other specimens (I.R.S.N.B. R.I4 (PI. lA), 10.8632, B.M.(N.H.) 25608
and 38950) show the same characteristics as those described above. The femur/
humerus ratio of I.R.S.N.B. 10.8632 is 65-6, as against the 67-5 recorded for the adult
specimen I.R.S.N.B. R.I5.
R.I5 also includes two distal tarsals and all five metatarsals. The bones are very
little disturbed and are of similar proportions to the same elements in the hind limb
EOCENE SEA-TURTLE
179
of modern sea-turtles. Distal tarsal III is rounded and similar to that of the species
Glarichelys knorri Zangerl (1958). The lengths of metatarsals II- V are 19 mm,
20 mm, 20-5 mm and 15 mm respectively.
Carapace and plastron (Reconstruction Fig. 13)
FIG. 13. Puppigerus cnmperi (Gray). Reconstructions of shell.
A. Carapace. B. Plastron.
Several excellent shells of P. camperi are housed in the Brussels Institute ; they
are numbers I.R.S.N.B. R.I3, R.I4, R.I5, 10.8402, IG. 8632, 10.9544, 1666 and the
lectotype I687/R.4. Most of them include remains of both carapace and plastron,
so that the task of description is much simpler than it would be if one had to rely
solely on British material. Comparative measurements of specimens from both
countries are listed in Table 2 to support the subjective synonymy of the species
P. camperi and P. longiceps. Variation in the neural and pygal plates of the several
carapaces is only very slight and the pattern of the central dermal plates is charac-
teristically constant ; this contrasts with the condition in Argillochelys antiqua,
where the relationship between the first and second neurals is inconstant and the
sizes of the last three extremely variable. In P. camperi the first neural is usually
biconvex and the last three neurals always become progressively shorter. A com-
parison with other eochelyines emphasizes the invariability of the central dermal
plate pattern.
i8o
PUPPIGERUS CAMPERI
A
5cm
5cm
FIG. 14. PiAppigervis camperi (Gray). Carapaces from above.
A. I.R.S.N.B. 10.8632. B. I.R.S.N.B. 10.1663.
In the juvenile specimens I.R.S.N.B. 10.8632 and G.S.M. 57266 the carapace is
not completely ossified and large costo-peripheral fontanelles are present along its
margin, from the nuchal to the pygal plates. In 10.8632 (Fig. I4A) the second
suprapygal is missing, perhaps because of imperfect preservation. As the animal
grows the costal and peripheral plates gradually occlude the lateral fontanelles
(Fig. 15) ; the carapace of the adult is completely ossified, e.g. in I.R.S.N.B. 10.9544
(PI. 76). This closure of the lateral fontanelles occurs only in Puppigerus and, in
consequence, the peripheral plates of that genus are larger than those of related forms.
Another change in the development of the carapace is seen in the lengthening and
rounding of the epidermal scutes in the adults, for those of the juveniles are rela-
tively broader and much more angular (Fig. 15). In specimen 10.9554 the outlines
of the vertebral scutes are double and indicate successive growth stages (PI. 76).
The ontogenetic changes described above for the Belgian specimens are also visible
in certain British carapaces, which range from the very well-preserved juvenile
G.M. 57266 to the large adult B.M.(N.H.) 38951.
All the British specimens are incomplete ; the main casualties are the peripheral
plates, which are known from very few specimens indeed. But, in spite of these
preservational defects, the carapaces of P. camperi can be easily recognized through
the description given above and by the constancy of the plate pattern.
EOCENE SEA-TURTLE
181
182 PUPPIGERUS CAMPERI
The plastra of the two Belgian specimens I.R.S.N.B. R.I4 and R.I5 (PI. i) are,
without doubt, the best examples of the ventral shell of P. camperi. Both have all
their plates and in R.I5 each plate is in its correct position. The epiplastra are shown
beautifully in the latter specimen and are typically wedge-shaped, like those of the
genus Catapleura (Schmidt 1944). The xiphiplastra are shorter and broader than
those of Argillochelys, sutural contact existing along their whole length, and their
notched contact with the hypoplastra is less acute. The difference between the
notched contacts of P. camperi and those of Eochelone brabantica is even more pro-
nounced. The specimens I.R.S.N.B. 10.8632 (PI. 8A), 16.8402 (individual plates),
and B.M.(N.H.) 25608, 28853, 38950 and 38951 (PI. 8B) also illustrate the form of the
plastron in P. camperi.
The central fontanelle, which Cuvier (1824) used as one of the characters justifying
his association of this form with the 'emydes', is a consistent feature throughout the
ontogeny of P. camperi (PI. 8). In forms such as Lepidochelys olivacea olivacea,
however (see Zangerl 1958, Abb. 27), this fontanelle varies greatly in size.
The plastral indices recorded for P. camperi show a high intraspecific variability,
with a range of 70-90 for plastral index A and of 65-75 for plastral index B (Table
2). It is therefore recommended that isolated plastral material should be identified
not only on these indices but also on other proportional differences, including the
slight variation in xiphiplastral lengths of the three genera Argillochelys, Eochelone
and Puppigerus.
The terminology of the various shell elements is explained by Zangerl (1969).
SUMMARY AND CONCLUSIONS
The account given represents a taxonomic and morphological study of all available
material hitherto referred to the species Lytoloma camperi, L. longiceps and L.
trigoniceps of Belgium and England. All this material is recognized as conspecific,
the rules of priority requiring that the species be called Puppigerus camperi.
The morphology of this species is mainly cheloniid but the pelvic girdle and hind
limb retain several primitive characters. The functional purpose of a combination
of cheloniid fore limb and toxochelyid hind limb was probably to enable alternate
slow cruising and rapid paddling (Zangerl 1953). Although this type of movement
is postulated for this species and many others of similar morphology, no light is
thrown on to the habitat or feeding habits of the animal. The jaws of P. camperi
are characteristic elements but they too give little information as to the likely feeding
habits. Dollo (1909) stated that Lytoloma bruxelliensis fed on oysters but, although
the feeding habits of turtles are in some species restricted to particular diets, they
generally vary according to the availability of food.
In Chelydra serpentina, the Recent snapping turtle, the form of the jaw suggests a
diet consisting exclusively of fish or other animals ; this, however, is not so, for the
turtle is known to consume large quantities of vegetable material (Lagler 1943).
Nor is a secondary palate an invariable indicator of a durophagous diet, for it occurs
in plant-eaters such as Chelonia my das.
The sediments in which P. camperi is found contain great quantities of vertebrate
and invertebrate material and, in the case of the London Clay, an abundance of plant
EOCENE SEA-TURTLE 183
material too. The size of the secondary palate varies considerably in the Eochelyinae
and this suggests a variation in diets, but as yet no one knows what P. camperi fed on.
The limb pattern and the suggested type of locomotion would tend to indicate a
wider variety of ecological niches in the Eochelyinae than is found in freshwater
forms. It is probable that the eochelyines dwelt mainly on the coast and in coastal
inlets but could also travel into the open sea.
As in the toxochelyid turtles described by Zangerl (1953), parasitic lesions are very
common. Some of the specimens are badly affected, with infestations occurring
mainly on the shell plates but also on the skulls. The skull infestations sometimes
penetrate the bone and may have been the cause of death. Thicker bone often sur-
rounds the cavities caused by the parasites.
Most of the London Clay and Bartonian specimens are disarticulated and in-
complete, but some specimens do retain attached skulls or limb fragments, indicating
that scavenging and current action were not severe.
Specimens are more frequently damaged (crushed and distorted) by post-deposi-
tional compaction and are often destroyed by pyritization. The Belgian material
occurs in a sandstone and is often complete in its preservation ; this suggests very
peaceful burial conditions.
ACKNOWLEDGMENTS
I should like to thank Drs E. Casier, A. J. Charig and R. Zangerl for their valuable
help and encouragement and Drs Charig and Zangerl for their reading of the manu-
script. Thanks are also due to Messrs C. A. Walker and P. J. Whybrow of the
British Museum (Natural History) for their assistance in the preparation of material.
I acknowledge the kind help and attention of Dr G. E. Quinet and the staff at the
Institut Royal des Sciences Naturelles, Brussels ; Miss J. Dobson of the Hunterian
Museum, Royal College of Surgeons, London ; Dr D. Russell of Paris ; Mr R. V. Mel-
ville, Dr R. Casey, Mr E. P. Smith and Mr C. J. Wood of the Institute of Geological
Sciences, London ; and Dr C. L. Forbes of the Sedgwick Museum, Cambridge. The
photographs were taken by Dr E. Casier, Mr T. W. Parmenter, Dr R. Zangerl and my-
self, and the figures organized with the help of Mr R. Andrews of Kingston.
This programme of research has been made possible by grants from the Natural
Environment Research Council and the Central Research Fund of London University.
ABBREVIATIONS
The names of Museum and other collections have been abbreviated as follows :
B.M.(N.H.) British Museum (Natural History), London
C.N.H.M. Field Museum of Natural History, Chicago
G.M. Geological Museum, Institute of Geological Sciences, London
H.M. Hunterian Museum, Royal College of Surgeons, London
I.R.S.N.B. Institut Royal des Sciences Naturelles de Belgique, Brussels
M.M. Maidstone Museum
R.Z. Rainer Zangerl's private collection
S.M.C. Sedgwick Museum, Cambridge
Y.P.M. Peabody Museum of Natural History, Yale University, New Haven
i84
PUPPIGERUS CAMPERI
Other abbreviations
a os angulare
art os articulare
boc os basioccipitale
bsph os basisphenoideum
cb condylus basioccipitalis
cex condylus exoccipitalis
ch internal narial opening
cor os coronoidum
d os dentale
exo os exoccipitale
fac foramen arteriae cerebralis
fh fossa hypophyeos
fja foramen jugulare
fn foramen nasale internum
fr os frontale
fs foramen nervi trigemini
i ilium
is ischium
jug os jugale
Cranial nerves
v trigeminal
vn facial
vin acoustic
mx os maxillare
opot os opisthoticum
orb orbit
p pubis
pa os praearticulare
pal os palatinum
par os parietale
pbf first principal brain flexure
pfr os prefrontale
pmx os preamaxillare
po os postorbitale
ptg os pterygoideum
qj os quadrato-jugale
qu os quadratum
sa os surangulare
sq squamosal
soc os supraoccipitale
v vomer
vest vestibule
IX
X
XI
XII
glossopharyngeal
> vagus and accessory
hypoglossal
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EOCENE SEA-TURTLE 185
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9-29, figs. 60-124.
1 86
PUPPIGERUS CAMPERI
ZANGERL, R. 1957. A parietal foramen in the skull of a Recent turtle. Proc. zool. Soc.
Calcutta Mookerjee Memorial vol. : 269-273, pi. 12.
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30-33-
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14, 2 : 7-40, figs. 2-23, 2 pis.
INDEX
The page numbers of the principal references are printed in bold type ; an asterisk (*)
denotes a figure.
All anatomical terms refer to the species Puppigerus camperi (Gray) .
Argillochelys, 161-3, 168, 170, 174, 182
antiqua, 179
cuneiceps, 168, 174 ; plate 6
atlas, elements of, pi. 5, fig. A
axillo-inguinal width, 159-60
Barton Beds, 158
basioccipital depression, 161, 165
Bracklesham Beds, 158, 165
braincase, 165, 170-2 ; see also under the
separate bones
Bruxelles, Sables de, 158, 165
carapace, 161-2, 165, 179-80, 179*, 180*,
181* ; pi. 5, fig. B ; plate 7
Caretta, 174
Carettinae, 161
Catapleura, 163, 165, 182
caudal vertebrae, 175-6
ceratobranchial arch, first, 173*
cervical vertebrae, 161, 174 ; plate 4
of Argillochelys cuneiceps, plate. 6
joints between, 162
Chelone anticeps, 163
crassicostata, 165, 168
longiceps, 155-6, 157, 160, 163, 165
trigoniceps, 155, 157-8, 163
'vanbenedeni' ', 177
Chelonia, 162, 171, 178
mydas, 156, 163, 170-1, 176-7, 182
Cheloniidae, 161, 175-7
Cheloniinae, 161
Chelydra, 178*
serpentina, 182
choanae, 168
comparative table of turtle genera, 162
copula, 173* ; pi. 2, fig. B
coracoid, 176 ; pi. 5, fig. E
Corsochelys, 174
haliniches, 172, 174, 177
dermal elements, 161
Dermochelys, 174
Desmatochelys lowi, 177
diagnosis, emended, of Puppigerus camperi,
165
dorsal vertebrae, 174-5 ; pi. 5, fig. B
ectopterygoid processes, 161, 165
Emydes de Bruxelles, de Sheppey, 163
Emys camperi, 155, 156, 157, 163, 165
cuvieri, 163
parkinsonii, 157, 163
endocranial cast, 172, 172*
entoplastron, 165
Eochelone, 161, 182
brabantica, 177, 182
Eochelyinae, 161, 165, 176-7, 183
Eochelys, 156-7, 160-1
longiceps, 155-7, 160, 163
epidermal elements, 161, 180
mosaic, 161
shields, 162
epiplastra, 161, 163, 165, 182
Eretmochelys, 163, 177, 178*, 178
imbricata, 177-8
Erquelinnesia, 157
Euclastes, 157
femur, pi. 5, fig. H
INDEX
i86a
foramen, midline, 169
fontanelles, 161
central, 163, 165, 182
costo-peripheral, 162, 165, 180
Glarichelys knorri, 179
humeral : femoral ratio, 161
humerus, 177 ; pi. 5, fig. D
hyo-hypoplastral suture, 160, 163
hyoid apparatus, 172-3, 173*
hypoplastron, 182
Idiochelys, 162
ilium, pi. 5, fig. G
interorbital bar, 159
ischium, 177-8 ; pi. 5, fig. G
jaw, lower, 172-4, 173* ; see mandible
jugal, 165, 1 68
Lepidochelys, 156, 162
kempi, 176
olivacea2, 182
limbs, 161-2, 176-9; see also under the
separate bones
London Clay, 158, 165
Lytoloma, 155-8, 160, 162
'bruxelliensis' , 158, 164, 182
camperi, 155, 158-60, 163, 182
crassicostatum, 158, 163
longiceps, 156-60, 163, 182
trigoniceps, 155, 157-9, 163, 175*. 182
'wemelliensis' , 158, 164
mandible, 161, 173* ; pi. 2, fig. B ; see also
jaw, lower
marginal shields, 162
maxilla, 165, 168
metatarsals, 178-9
nares, external, 161
internal, 158, 161, 165
variation in position with size, 168
neurals, 161, 165
neural plates, 159, 161-2
shields, 159
occipital shield, 161
orbit, 159, 161
Pachyrhynchus, 157
longiceps, 163
trigoniceps, 163
palate, 158
secondary, 161-2, 165
palatine, 161, 165
parasitic lesions, 183
parietal foramen, 169 ; pi. 3, fig. A
pectoral girdle, 176-9
pelvic girdle, 176-9, 178*
peripheral plates, 162
plastral indices, 159-60, 165, 182
plastron, 159-63, 165, 179, 179*, 182 ; plate
8
Plesiochelidae, 161
Plesiochelys, 162
pleural shields, 162
premaxilla, 161, 165, 168
Pseudemys ornata, 175
pterygoid, 161, 165
pubis, 178 ; pi. 5, figs. F, G
Puppigerus, 155-7, I^o, 161, 162, 163
camperi, 153-86 passim, 163-83 ; plates
i-5, 7, 8
description, 165-82
diagnosis, 165
historical review, 156-61
lectotype, 155, 164*
measurements and indices, 158-60
occurrence, 165
referred specimens, 164
type material, 155, 163
crassicostatus, 168
longiceps, 155, 161, 163, 179
trigoniceps, 155
pygals, 165
quadrato-jugal, 165, 168
radius, 177
sacral vertebrae, 175-6
sacrum, 175*
scapula, 176 ; pi. 5, figs. C
sea- turtle, Eocene, of N. Europe, 153-86
skeleton, 162, 165
skull, 165-75, 166*, 167*, 169*. 170* ; pi. 2,
figs. A, C, D, E, F ; plate 3
compared with Testudo denticulata, table
169
measurements and indices, 168
snout, 158, 161, 165
Stegochelys, 171
suprapygal plates, 162
tarsals, 178-9
Testudo corticata, 156, 163
i86b INDEX
denticulata, 169, 170* joints between, 162
Thalassemydidae, 161 dorsal, 174-5 ; pi. 5, fig. B
Thalassemys, 162 sacral and caudal, 175-6
'Tortue Franche', 163 vertebral column, 161
Toxochelyidae, 161, 176-7 scutes, 161-2
Toxochelys, 162, 171, 177, 178* vomer, 161, 165
latimeris, 176-7
moorevillensis, 177-8 Wemmel, Sables de, 158, 165
turtle, marine, Eocene, of N. Europe, 153-86
xiphiplastral index, 160
ulna, 177 tip, 1 60
xiphiplastron, 160, 162-3, I&5
vertebrae, cervical, 161, 174 ; plate 4
RICHARD THOMAS JONES MOODY, Ph.D.
KINGSTON POLYTECHNIC
PENRHYN ROAD
KINGSTON-UPON-THAMES
SURREY
ENGLAND
PLATE i
Puppigerus camper* (Gray)
A. I.R.S.N.B. R.I4. From below xj
B. I.R.S.N.B. R. 15. From below xj
Bull. Er. Mus. nat. Hist. (Geol.) 25, 2
PLATE i
PLATE 2
Puppigerus camperi (Gray)
I.R.S.N.B. 10.8402
A. Skull, from above x |
B. Mandible and copula x
C. Skull from below x f
D. Skull from left side x f
E. F. Skull in section x f
Bull. Br. Mus. nat. Hist. (Geol.) 25, 2
PLATE 2
U
CD
UJ
PLATE 3
Puppigerus camperi (Gray)
Skulls, from above
A. I.R.S.N.B. R.ig showing parietal foramen
B. I.R.S.N.B. R.i8
C. I.R.S.N.B. R.i6
Bull. Br. Mus. nat. Hist. (Geol.) 25, 2
PLATE 3
E
E
o
ID
PLATE 4
Puppigerus camperi (Gray)
B.M.(N.H.) 28853
Cervical vertebrae 2-8
A. From right side
B. From in front
C. From behind
D. From above
E. From below
Bull. Br. Mus. nat. Hist. (Geol.) 25, 2
< DO U
CD
D
U
D
PLATE 4
LU
01
in
CD
00
LU
PLATE 5
Puppigerus camperi (Gray)
B.M.(N.H.) 28853
A. Elements of atlas x 2
B. Carapace and dorsal vertebrae from below
C. Scapulae
D. Right humerus
E. Right coracoid
F. Right pubis
G. Left pubis, ilium and ischium
H. Left femur
(C-H, x ii)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 2
PLATE 5
LiJ
PLATE 6
Argillochelys cuneiceps (Owen)
S.M.C. 20937
Cervical vertebrae i -8
A. From right side
B. From in front
C. From behind
D. From above
E. From below
Bull. Br. Mus. nat. Hist. (Geol.) 25, 2
tc »
PLATE 6
G
D
w
OJ
* *
CD
«t 4
o>
00
DQ
G Q
LU
PLATE 7
Puppigerus catnperi (Gray)
Carapaces from above
A. I.R.S.N.B. R.i3
B. I.R.S.N.B. 10.9544
Bull. Br. Mus. nat. Hist. (Geol.) 25, 2
PLATE 7
t 'I
1 : V
PLATE 8
Puppigerus camperi (Gray)
Plastra from below
A. I.R.S.N.B. 10.8632
B. B.M.(N.H.) 38951
Bull. Br. Mus. nat. Hist. (Geol.) 25, 2
PLATE 8
o
col
u
in
A LIST OF SUPPLEMENTS
TO THE GEOLOGICAL SERIES
OF THE BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
1. Cox, L. R. Jurassic Bivalvia and Gastropoda from Tanganyika and Kenya
Pp. 213 ; 30 Plates ; 2 Text-figures. 1965. £6.
2. EL-NAGGAK, Z. R. Stratigraphy and Planktonic Foraminifera of the Upper
Cretaceous — Lower Tertiary Succession in the Esna-Idfu Region, Nile Valley,
Egypt, U.A.R. Pp. 291 ; 23 Plates ; 18 Text-figures. 1966. £10.
3. DAVEY, R. J., DOWNIE, C., SARJEANT, W. A. S. & WILLIAMS, G. L. Studies on
Mesozoic and Cainozoic Dinoflagellate Cysts. Pp. 248 ; 28 Plates ; 64 Text-
figures. 1966. £7.
3. APPENDIX. DAVEY, R. J., DOWNIE, C., SARJEANT, W. A. S. & WILLIAMS, G. L.
Appendix to Studies on Mesozoic and Cainozoic Dinoflagellate Cysts. Pp. 24.
1969. Sop.
4. ELLIOTT, G. F. Permian to Palaeocene Calcareous Algae (Dasycladaceae) of
the Middle East. Pp. in ; 24 Plates ; 17 Text-figures. 1968. £5.12^.
5. RHODES, F. H. T., AUSTIN, R. L. & DRUCE, E. C. British Avonian (Carboni-
ferous) Conodont faunas, and their value in local and continental correlation.
PP- 3*5 ; 31 Plates ; 92 Text-figures. 1969. £11.
6. CHILDS, A. Upper Jurassic Rhynchonellid Brachiopods from Northwestern
Europe. Pp. 119 ; 12 Plates ; 40 Text-figures. 1969. £4.75.
7. GOODY, P. C. The relationships of certain Upper Cretaceous Teleosts with
special reference to the Myctophoids. Pp. 255 ; 102 Text-figures 1969
£6.50.
8. OWEN, H. G. Middle Albian Stratigraphy in the Anglo-Paris Basin. Pp.
164 ; 3 Plates ; 52 Text-figures. 1971. £6.
g. SIDDIQUI, Q. A. Early Tertiary Ostracoda of the family Trachyleberididae
from West Pakistan. Pp. 98 ; 42 Plates ; 7 Text-figures. 1971. £8.
10. FORKY, P. L. A revision of the elopiform fishes, fossil and Recent. Pp. 222 ;
Text-figures. 1973. £9.45.
Printed in Great Britain by John Wright and Sons Ltd. at The Stonebritlge Press, Bristol B$4 jNU
THE SHELL STRUCTURE OF
SPIRIFERIDE BRACHIOPODA
D. i. MACKINNON
BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
GEOLOGY Vol. 25 No. 3
LONDON: 1974
22AUG!
THE SHELL STRUCTURE OF -
SPIRIFERIDE BRACHIOPODA
BY
DAVID IRONSIDE MACKINNON
\
Department of Geology University of Canterbury
Christchurch New Zealand
Pp 187-261 ; 32 Plates ; 27 Text-figures
BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
GEOLOGY Vol. 25 No. 3
LONDON: 1974
THE BULLETIN OF THE BRITISH MUSEUM
(NATURAL HISTORY), instituted in 1949, is
issued in five series corresponding to the Departments
of the Museum, and an Historical series.
Parts will appear at irregular intervals as they
become ready. Volumes will contain about three or
four hundred pages, and will not necessarily be
completed within one calendar year.
In 1965 a separate supplementary series of longer
papers was instituted, numbered serially for each
Department.
This paper is Vol. 25, No. 3, of the Geological
(Palaeontological) series. The abbreviated titles of
periodicals cited follow those of the World List of
Scientific Periodicals.
World List abbreviation :
Bull. Br. Mus. nat. Hist. (Geol.)
Trustees of the British Museum (Natural History), 1974
TRUSTEES OF
THE BRITISH MUSEUM (NATURAL HISTORY)
Issued 26 July, 1974 Price £6.70
THE SHELL STRUCTURE OF
SPIRIFERIDE BRACHIOPODA
By DAVID IRONSIDE MACKINNON
CONTENTS
Page
SYNOPSIS .......... 189
I. INTRODUCTION ......... 190
II. TECHNIQUE OF SPECIMEN PREPARATION ..... 191
III. SHELL STRUCTURE OF Spiriferina walcotti (Sowerby) . . . 191
(a) The shell succession . . . . . . . 192
(i) Periostracum ....... 192
(ii) Primary layer ...... 193
(iii) Secondary layer ...... 195
(b) Punctation . . . . ..... 196
(c) Hollow spines . . . . . . . .196
(d) Concentric growth lines and mantle retraction . . 198
(e) Muscle attachment areas ...... 201
(i) Pedicle valve . . . . . . .201
(ii) Brachial valve ....... 203
(iii) Functional considerations ..... 205
(f) The brachidium ........ 206
(g) Articulation . . . . . . . .210
IV. SHELL STRUCTURE OF OTHER SPIRIFERIDA .... 212
(a) Atrypidina ......... 212
(i) Atrypacea ....... 212
(ii) Dayiacea ....... 218
(b) Retziidina ......... 220
(c) Athyrididina . . . . . . . .221
(i) Athyridacea . . . . . . .221
(ii) Koninckinacea ....... 225
(d) Spiriferidina ........ 229
(i) Cyrtiacea . . . . . . .229
(ii) Suessiacea ....... 230
(iii) Spiriferacea ....... 232
(iv) Spiriferinacea . . . . . . . 238
(v) Reticulariacea ....... 239
(e) Thecospira ......... 240
V. STRUCTURE OF THE BRACHIDIUM AND INFERRED DISPOSITIONS OF
THE LOPHOPHORE IN SPIRIFERIDA ...... 243
(a) Structure of spiralia ....... 243
(b) Inferred dispositions of the spiriferide lophophore . . 251
VI. CONCLUSIONS. ......... 254
VII. ACKNOWLEDGEMENTS ........ 256
VIII. REFERENCES ......... 256
INDEX .......... 258
SYNOPSIS
By studying the growth and structure of the shell of Spiriferina walcotti (Sowerby), a standard
for the skeletal fabric of the order Spiriferida has been erected. Apart from the development
igo SHELL STRUCTURE
of the spiral brachidium, shell growth involving deposition of primary and secondary calcareous
layers (and also, presumably, a periostracum) in Spiriferina appears to have been little different
from that of living Terebratulida. In many stocks, however, including the Atrypacea, Dayiacea,
Reticulariacea, Koninckinacea and some Athyridacea and Spiriferacea, a tertiary layer similar
to that deposited in the living terebratulacean Gryphus vitreus (Born) has been identified. Apart
from the development of peripheral tubercles in Thecospiridae and some Koninckinacea (which
are both assigned to the Spiriferida) the shell structure of all remaining spire-bearers does not
differ markedly from that of living Rhynchonellida or Terebratulida.
The ultrastructure of the spiral brachidia of a number of genera has been examined and two
distinct growth patterns have been recognized. 'Single-sided' growth is characteristic of the
athyrididine spiralium whereas 'double-sided' growth is characteristic of all other spiriferides
examined. Consideration is given to the disposition of the spiriferide lophophore.
I. INTRODUCTION
THE advent of the electron microscope has led to an upsurge in studies relating to
the shell structure of living and fossil Brachiopoda. The most significant contribu-
tion to date, with respect to articulate Brachiopoda, has been that of Williams (igGSa)
in which it was shown that a triple division of the shell into periostracum, and
primary and secondary calcareous layers, is characteristic of most members of this
major class. By studying the soft tissues as well as the calcareous exoskeleton of
living Rhynchonellida and Terebratulida, Williams was able to rationalize shell
growth in terms of the secretory behaviour of individual outer epithelial cells. In
dealing with the Spiriferida Williams (i968a : 31-34) referred briefly to the skeletal
fabrics of a number of atrypidines, athyridines, retziidines and spiriferidines, showing
that in general they possessed a shell ultrastructure similar in many ways to that
found in Recent Rhynchonellida and Terebratulida, but it was outside the scope of
that report to include a more detailed survey of the order. This paper is intended as
a contribution towards a greater understanding of the processes of shell deposition
within the phylum from both a functional and evolutionary standpoint.
To make sense of a comparative study of the shell fabrics of fossil Spiriferida,
investigations must be based on a workable classification. In this exploratory
survey the Treatise classification, as erected by Boucot, Johnson, Pitrat and Staton
(1965) has been followed but only down to the rank of superfamily. As will be shown,
below this level of classification trends in ultramicroscopic shell variation, as well as
gross morphological distinctions, become less clearly defined.
The fact that no spiriferide genera (as far as is known) survive to the present day
has necessitated the selection of a suitable fossil representative as a standard model
for the skeletal fabric of the order. Spiriferina walcotti (Sowerby) fits this role well
for, apart from being a member of the last surviving spiriferide stock, its mode of
preservation is normally very good and adequate numbers of complete specimens
may be readily collected and prepared for study. Consequently a complete section
of this paper is devoted to a description of the shell structure of Spiriferina walcotti
prior to consideration of the skeletal fabrics of the order as a whole.
One aspect of spiriferide morphology which has excited some interest in recent
years has been the problem of establishing the nature and disposition of the lopho-
phore which must have been supported by the calcareous spiralia. With this thought
in mind, the structure of the spiralia of as many genera as possible has been studied
SPIRIFERIDE BRACHIOPODA 191
and compared with the structure of the calcareous supports in living Terebratulida.
Since the orientation of the lophophore in living Terebratulida can be determined in
relation to the disposition of the ascending and descending branches of the calcareous
loop, the possibilities of applying these findings to the Spiriferida have been in-
vestigated.
II. TECHNIQUE OF SPECIMEN PREPARATION
Both surfaces and sections of calcareous shells were examined under a Cambridge
'Stereoscan' scanning electron microscope. Initially specimens were embedded in
Epon Araldite resin then cut and ground, first on a diamond grinder and then on fine
grade (C6oo) silicon carbide paper. A relatively scratch-free finish was obtained by
using a paste of Aloxite optical smoothing powder along with the silicon carbide
paper. Surfaces prepared in this manner were finally polished on a cloth-covered disc
which was impregnated with stannic oxide or slow-cutting polishing alumina. Before
mounting, the embedded specimens were cut to a convenient area and thickness and
ultrasonically cleaned for a few minutes in a mild detergent solution, then in acetone.
Fragments of internal or external shell surfaces requiring investigation were cleaned
in the same way. Once dry, specimens were mounted on aluminium stubs using a
conductive adhesive (Lo-Kitt) then fixed on a rotatable table in a vacuum evaporator
and coated with a thin deposit (about 0-03-0-05 jum in thickness) of gold/palladium
alloy. A thin metallic coating of this nature is necessary when examining calcareous
shell fragments in order to render the specimens conductive and prevent charge
build-up.
All important 'Stereoscan' observations were recorded photographically. In
certain cases it was found that the size of skeletal components, in particular secondary
layer fibres, was such that individual 10 x 10 cm prints did not provide a sufficiently
detailed overall view of the area under investigation. To overcome this lack of
structural detail a montage of overlapping prints, which had been photographed at
higher magnifications, was constructed. In general, a 20 per cent overlap was
required to produce a reasonable match-up of corresponding features in adjacent
prints.
All mounted specimens used in this study have been presented to the British
Museum (Natural History) and retain the registered numbers BB 58878 to BB 59009.
III. SHELL STRUCTURE OF SPIRIFERINA WALCOTTI (SOWERBY)
Spiriferina walcotti (Sowerby) occurs within the British Lias and is especially
common in the highly attenuated sequence of Lower Liassic rocks around Radstock
and Bath. In this area, commonly referred to as the 'Radstock Shelf, the state of
preservation of the shell is normally very good and complete specimens, with fully
articulated valves, are abundant. It is convenient, therefore, to consider this
species of the last surviving spiriferide genus as a model for the skeletal fabric of the
order and, by studying the ultrastructure of its shell, reconstruct the morphology and
disposition of its mantle. The restored species may then be used as a standard with
which all other Spiriferida may be compared.
192 SHELL STRUCTURE
Tutcher & Trueman (1925 : 595) have given a detailed description of many
fossiliferous localities within the Radstock area, though regrettably a number of
sections and quarries listed by them are now overgrown with thick vegetation or
filled in with earth and rubble. Fortunately Bowlditch Quarry (ST 668559) north
of Radstock and Hodder's Quarry (ST 674584), Timsbury, both sources in the past
of some of the finest specimens of 5. walcotti, are still accessible. All specimens
examined during the present investigation came from either one or other locality.
Before considering the microstructure of the shell of S. walcotti, it seems appropriate
to describe the morphology of the shell because, as far as is known, no up-to-date
account of the species is available. Certainly a knowledge of the morphology of
exoskeletal outgrowths and their relationship with the shell is essential before the
microstructure of critical sections can be fully understood. The following diagnosis
supplements the descriptions given by Davidson (1852 : 25) and Hall & Clarke
(1894 : 51) :
Shell moderately transverse in outline, with rounded cardinal extremities ; bi-
convex in profile, anterior commissure uniplicate, distinct fold and sulcus ; lateral
slopes with distinct, rounded, simple costae ranging from 2 to 5 (modally 4) on each
slope. Ventral interarea gently curved, dorsal interarea low ; both traversed by
growth lines, fine striae intermittently developed normal to transverse growth lines.
Triangular delthyrium, partly restricted by a pair of dental ridges (cf. Dunlop
1962 : 491) ; low triangular notothyrium. Surface further ornamented by concentric
growth lines and numerous fine, tubular spines ; shell endopunctate.
Interior of pedicle valve with high, dorsally pointed median septum extending for
almost half the length of the valve and bearing broad, well-defined adductor muscle
scars ; diductor and ventral adjuster muscle scars impressed on valve floor on either
side of median septum. Teeth prominent ; dental plates short, diverging from umbo
and terminating on the valve floor just postero-laterally to the diductor muscle
scars.
Interior of brachial valve with triangular cardinal process, usually striated parallel
to the median plane, bounded laterally by posterior walls of inner socket ridges ;
dorsal adjuster scars deeply impressed on the crural bases, situated just antero-
laterally to the cardinal process and each bounded by an inner socket ridge. Crura
broad, supporting laterally directed spires with as many as 15 convolutions ; primary
lamellae united by single jugum ; anteriorly facing edges of spiral lamellae spinose ;
two pairs of dorsal adductor muscle scars with the anterior pair more prominently
inserted on floor of valve.
(a) The shell succession
(i) Periostracum
The chances of finding traces of the organic constituent of the shell of Spiriferina
that are identifiable under the electron microscope are very small. However,
amino-acids have been recovered by Jope (1965 : Hi6i) from several spiriferide
shells and it is highly likely that the organic parts of the exoskeletal succession were
SPIRIFERIDE BRACHIOPODA
193
similar to those found in living species. In particular, a periostracum would have
been necessary as a seeding sheet for the mineral part of the shell, and membranes
must also have ensheathed the fibres of the secondary shell. Both constituents must
have played a decisive part in determining the ultrastructure of the primary and
secondary calcareous shell.
(ii) Primary layer
Although the external surface of the primary layer is finely granular a distinct
lineation is visible with the long axes of the particles radially aligned (PI. i, fig. i).
At intervals of about 20 /xm, fine concentric growth lines are superimposed on this
fabric (PI. i, fig. 2) so that, whilst no remnant periostracal covering remains, an
impression of its basal membrane is preserved. Anterior to the base of each spine
the surface of the shell is dissected by a prominent longitudinal groove (PI. i, fig. 3)
whilst several more conspicuous grooves, also aligned parallel to the long axis of the
shell and spaced from 4 to 6 /u,m apart, are deflected around the posterior of the spine
base (PI. i, fig. 4). If the dimensions of terminal faces of fibres situated around the
periphery of the valve margins can be taken as a guide to the size of outer epithelial
cells located close to the edge of the outer mantle lobe (about 5 /urn wide), then it is
reasonable to assume that the longitudinal grooves posterior to each spine base,
being similarly spaced, correspond to the lateral boundaries of rows of cuboidal
epithelium.
In mature specimens of Spiriferina, the thickness of the primary layer can vary
from about 30 /mi, close to the umbo, to 100 p,m or more at the anterior commissure
(Text-fig, i). Since deposition of the primary layer is restricted to a narrow zone of
outer epithelial cells located around the shell edge, the observed thickening of the
primary layer can be interpreted as a progressive widening of this zone with age.
J 10
'£ 9
o 8
«j
^ 7
! 6
4 6 8 10 12
Distance from Umbo (mm)
14
16
FIG. i. Graph showing the increase in the thickness of the primary layer from umbo to
anterior commissure in a brachial valve of Spiriferina. Broken lines denote regression
planes of overlapping growth lamellae.
194 SHELL STRUCTURE
Unless the dimensions of newly proliferated cells increase drastically as the brachiopod
approaches maturity, a widening of the zone of primary shell deposition must be
accompanied by an overall increase in the number of cells involved in secreting that
layer. If such is the case, the widening of the primary shell secretory zone must also
reflect an increasing delay with age in the change-over to secondary shell deposition
(cf. Williams iQ7ia : 58). Alternatively, primary layer thickening may be related
to an increase in the marginal angle of the shell which may result from a reduction
in the migration rate of cells in the conveyor-belt system of the outer mantle lobe.
In section, a twofold division of the primary layer is recognizable (PI. i, fig. 5). It
is possible to distinguish between an outer, finely granular, porous part which grad-
ually merges into a more compact inner portion composed of crystallites (averaging
less than 10 /mi in length) orientated with their long axes normal or posteriorly
inclined to the isotopic boundary (Westbroek 1967 : 23) defining the junction between
the primary and secondary shell layers. Electron micrographs of random, oblique
sections of Spiriferina show that grain boundaries of primary layer crystallites are
regularly found in continuity with the first-formed, inwardly convex boundaries of
secondary layer fibres so that organic membranes, known to ensheath the latter,
could also have extended deep within the primary layer. In radial sections, a faint
banding is occasionally seen which runs posteriorly at a low angle from the external
surface to the internal boundary with the secondary layer. The banding is con-
sidered to be depositional, and thus merits recognition as a superficial (isochronous)
shell unit boundary, as defined by Westbroek. Such radial sections serve to establish
the relationship between these surfaces and the calcareous skeletal constituents when
the first formed fibres occur as long rods dipping gently towards the anterior shell
edge. In addition, the crystallites of the primary layer are, in general, posteriorly
inclined to the isotopic surfaces between the primary and secondary layers, but
normal to the observed depositional banding.
As this twofold division of the primary layer is not characteristic of Recent
Rhynchonellida and Terebratulida, it is possible that the textural variation is secon-
dary in origin. If, for some unknown reason, the primary layer of Spiriferina were
especially prone to recrystallization, the process would be confined within a space
bounded externally by compacted grains of enclosing sediment and internally by the
fibres of the secondary shell. Recrystallization normal to these two interfaces
might then have given rise to two contrasting crystalline textures growing towards
one another. However, specimens of the terebratulacean Lobothyris punctata
(Sowerby), collected from the same localities as Spiriferina, exhibit a primary layer
texture closely resembling that of living Terebratulida, whilst the fibres of the secon-
dary shell of both species are in an identical state of preservation. Such evidence
suggests that textural differences in the primary layer of Spiriferina are original.
The twofold nature of the primary shell is not unique to Spiriferina. Armstrong
(i9&8a : 184), in describing the microstructure of the shell of the spiriferide Subansiria
sp. from the Permian rocks of Queensland, Eastern Australia, distinguished within its
primary layer an identical granular outer part and finely crystalline inner portion.
Armstrong maintained that the boundaries between the primary layer components
of Subansiria sp. are as distinctive as the inter-fibre junctions in the secondary shell.
SPIRIFERIDE BRACHIOPODA 195
Such a comparison prompted him to postulate the deposition of organic membranes
around the crystals of the primary layer. The outer granular portion of the primary
layer, he suggested, may have been the product of a transitional phase of organic-
mineral deposition following the secretion of the periostracum and preceding forma-
tion of the more regular crystals.
Growth of the primary layer in Recent Rhynchonellida and Terebratulida, as
described by Williams (i968a), could not account for the twofold structure of that
layer in Spiriferina. In living articulates, the first formed seeds of calcite are
secreted by cells situated at the tip of the outer mantle lobe onto an embedding
protein cement comprising the innermost surface of the periostracum. Initially the
seeds tend to be concentrated in zones separated by inwardly directed bars of
periostracum and isolated from one another by membranous projections of the cells
(microvilli) attached to the periostracum. As deposition continues, the crystallites
grow and overlap one another across intercellular boundaries, but microvilli continue
to permeate the primary layer to give its inner surface a highly porous appearance.
However, observations recorded above suggest that, although growth of the primary
layer of Spiriferina started in similar fashion with deposition of the first calcite
crystallites onto an embedding protein sheet forming the internal surface of the
periostracum, the crystallites did not quickly coalesce. Instead they were kept
isolated from one another by a fine membranous web extending inwards from the
periostracum and deposited simultaneously with the crystallites by the outer
epithelial cells. As an increasingly thick wedge of primary layer was deposited,
organic secretion became less prevalent and many connecting membranes became
pinched out. Hence crystallites amalgamated with one another and imparted to
the inner half of the layer a more homogeneous appearance. Finally at a certain
distance from the shell edge, organic secretion became restricted to an arcuate sector
of the secreting plasmalemma and deposition of the secondary layer began.
(iii) Secondary layer
The secondary shell layer is built up from orthodoxly stacked fibres. On the
internal surface of the shell, the terminal faces of the overlapping fibres produce the
standard secondary shell mosaic pattern (PI. i, fig. 6). Whilst secondary generative
zones are known to occur in certain areas of the outer epithelium, the main zone of
cell proliferation and fibre formation is located around the shell edge. In this area,
the young fibres of Spiriferina with terminal faces no more than 5 ^m wide grew
normal to the commissure. The consistency of this initial growth direction is verified
by examination of the external surface of specimens from which the primary layer
has broken off during removal from the enclosing sediment. In such specimens, the
freshly exposed trails of the secondary layer fibres are radially disposed over the
entire shell surface. When young fibres of Spiriferina come to occupy a position up
to about 100 jum behind the leading edge of the secondary shell mosaic, they become
reorientated, broadly speaking, in a sub-parallel arc ; clockwise in the right half of
the valve, anti-clockwise in the left.
Terminal faces of mature fibres are spatulate, normally 30 ^m long and 15 pm at
maximum width. However, on some parts of the inner shell surface, they may
ig6 SHELL STRUCTURE
become elongate with long exposed trails. Other more drastic changes take place
in those fibres underlying the muscle attachment areas, but these will be considered
separately. Small localized convolutions in the form of spiral arcs and tight S-shaped
patterns may be found in most parts of the shell. Similar minor modifications occur
in the shells of a number of Recent articulates (Williams ig68a : 9) and are considered
simply to reflect small epithelial adjustments in adjacent zones of the internal surface.
In gerontic forms, radial fibre growth around the commissure becomes less pre-
valent since the normal secretory regime in this area is disrupted by repeated mantle
retractions. This particular aspect of mantle behaviour and shell deposition will,
however, be dealt with separately.
(b) Punctation
The shell of Spiriferina is endopunctate. As in living Terebratulida, perfectly
interlocking fibres of the secondary layer fashion and preserve the cylindroid shape
of the canals which measure, on average, 30-40 /mi in diameter. This is well dis-
played on the internal surfaces of Spiriferina where the advancing fibres are momen-
tarily deflected from their paths of growth so as to sweep around the puncta, but
thereafter continue on their previous course (PI. 2, fig. i). In some cases where a
fibre trail lies directly in line with a caecum, the fibre may terminate on one side of
the cavity and reappear, without any noticeable change in size or shape, on the side
directly opposite. In section, the fibres on either side of the puncta arch outwards
towards the primary layer (see PI. 3). The puncta so defined do not run quite normal
to the shell layers but slope anteriorly from the shell exterior at a steep angle of
about 80 degrees. Within the umbonal region of the pedicle valve, groups of
branching puncta are found. Towards the interior of the shell up to five discrete
canals may merge into one central canal. Such branched puncta are considered to
have formed as a result of the coalescence of originally discrete puncta due to
extensive deposition of calcite in that part of the shell.
When viewed from the exterior, the puncta of Spiriferina usually break the surface
of the primary layer, but in several cases fragmentary distal coverings, about i /xm
thick, were observed in situ (PI. 2, fig. 2). This thin layer of primary shell material
is perforated by densely distributed canals, each measuring approximately 500 nm
in diameter (PI. 2, fig. 3).
Since the perforate canopies covering the distal ends of puncta in Spiriferina are
so unmistakably like those in living Terebratulida (MacKinnon i97ia), it seems
certain that the puncta of Spiriferina must have accommodated caeca virtually
identical in ultrastructure with those in living endopunctate brachiopods.
(c) Hollow spines
The micro-ornament visible on the exterior surface of Spiriferina consists of a
variably dense concentration of hollow spines, on average 80 ^m in diameter at their
bases and tapering distally to about 35 ju.m, which project at low angles towards the
SPIRIFERIDE BRACHIOPODA
197
commissure (PL i, fig. 2). They are usually broken, but a few may remain more or
less intact between costae where stalks up to 2 mm in length have been found. All
spinose outgrowths are composed solely of primary shell material, but the narrow
canals running through the spines, on average 30-40 /mi wide in mature specimens,
do not terminate at the primary /secondary shell layer boundary. Starting from the
shell exterior, a canal can be traced running posteriorly parallel to the length of a
spine until it reaches the spine base, whereupon it bends sharply through 90 degrees
before passing through the remainder of the secondary layer (Text-fig. 2) . Through-
out the secondary layer, the walls of the canals are fashioned by fibre trails which are
deflected around one side or the other in a manner identical to that found in puncta.
On the inner shell surface, the cylindroid hollows forming both puncta and spine
canals are indistinguishable. Although the distal ends of spines are broken off, no
blocking up of canals due to subsequent shell deposition has been observed in the
surviving basal parts.
hollow spine
perforate canopy
of punctum
punctum
FIG. 2. Block diagram showing the relationship between a hollow spine, a punctum and
the calcareous shell succession in Spiriferina. Anterior commissure of shell located
beyond the left-hand margin of the diagram.
The density of distribution of spinose outgrowths is variable over the whole shell
surface. Within 5 mm of the umbo, which incorporates the earliest formed parts of
the shell, the surface density of hollow spines rarely exceeds 5 per mm2. Around the
commissure of mature specimens, however, the density is appreciably greater, rising
to as much as 35 per mm2. In general, the spines do not conform to any recognizable
pattern on the shell exterior, but close to the anterior commissure of mature
IQ8 SHELL STRUCTURE
specimens where the concentration of spinose outgrowths is densest, localized groups
of spines appear to be arranged 'in quincunx'. In such areas, a one-to-one corre-
spondence exists between spine bases and puncta with the puncta set out in alternat-
ing rows between spine bases.
Clearly the spines were built up very quickly by the secretion of calcite in small
circumferential generative zones of outer epithelium located close to the tip of the
outer mantle lobe, but they did not continue to increase in length throughout life as
happened in certain strophomenides. Whereas strophomenide spines continued to
grow indefinitely with accretion of primary and secondary shell material (or were
eventually sealed off), the spines of Spiriferina grew only during the period in which
adjacent cells were employed in primary shell formation. Once the underlying
epithelium changed to secreting the secondary layer, growth of the spines ceased.
The structure and distribution of the spines provide little indication of their
function. Unlike the hollow spines of genera such as Acanthothiris (Rudwick
1965 : 610), and certain Siphonotretacea (Biernat and Williams 1971 : 429), the spines
extending from the surface of Spiriferina were not long or large enough to have
functioned efficiently as protective grilles. Even if the shell were closed, spines
extending from both valves would not have intersected. Rudwick (1965 : 610)
suggests that the hollow spines of Acanthothiris probably accommodated sensory
organs which could have provided the brachiopod with effective 'early-warning'
protection against potentially harmful agents in the environment. The tips of
growing spines, however, would have been occupied by generative cells involved
in the proliferation of new cells and the secretion of mucopolysaccharide and perio-
stracum. Thus the presence of these external covers would surely have militated
against any chemo-sensitivity of the tips of spines developed as extensions of the
shells of any brachiopod, including Spiriferina. However, since the shell exterior
is to a large extent free from boring organisms and any encrusting epifauna, it is
possible that the function of the spines was protective. As Owen & Williams
(1969 : 200) have pointed out, the typical brachiopod exterior seems frequently to
attract a rich benthonic microfauna, consisting of bryozoans, sponges, algae etc.
Obviously an irregular surface topography, broken up by spines, would tend to
hinder and discourage the settlement of such organisms onto the surface of the
periostracum.
(d) Concentric growth lines and mantle retraction
The presence of concentric growth lines on the outer surfaces of both valves is
characteristic of a great number of Spiriferida. These are considered to be the result
of a series of successive pauses or even complete breaks in deposition affecting the
normal pattern of radial growth. In the past, palaeontologists have found sets of
growth lines to be of great systematic value in recognizing a number of successive
ontogenetic stages in many genera. Krans (1965 : 87), using a dry peel technique
with carefully orientated sections, has made a study of the shell growth in a number
of Devonian Spiriferida and has distinguished three main types of growth features.
These are :
SPIRIFERIDE BRACHIOPODA 199
(1) Slight flexures where the shell layers are bent into a small kink due to a pause
in radial growth whilst deposition of calcite continues.
(2) Overlapping growth lamellae where the primary and secondary shell layers are
bent around to face posteriorly inwards before returning to normal radial
growth.
(3) Free growth lamellae caused by a distinct break in deposition of calcite with a
strip of mantle around the shell edge actually detaching itself from a part
which it has already formed. In addition, the mantle undergoes an abrupt
retraction before returning to the normal course of deposition.
Such observations are comparable with those made by Brunton (1969) and Williams
(197 1 a) on Recent Rhynchonellida and Terebratulida, but the signs of depositional
pauses or breaks described for Spiriferina, though similar, are not identical.
Minor fluctuations in the rate of shell deposition, as well as more drastic physio-
logical changes in the secretory role of outer epithelial cells situated around the
mantle edge, contributed to the appearance of a variety of concentric growth lines
over most of the shell exterior. The finest, which are microscopic growth lines
normally no more than 20 /mi apart, are surface features unaccompanied by any
differential thickening of the primary layer (PI. i, figs. I, 2). Where there are slight
flexures in the shell layers, each producing a concentric ridge in the order of 100 /mi
in amplitude, the primary layer is warped in a manner analogous to monoclinal
folding, whereas the underlying fibres of the secondary layer are crowded together
and display cross-sectional outlines different from those either in front of or behind
the modified zone (PI. 2, fig. 5). Most of the major overlapping shell units are found
around the commissures of mature specimens. In radial section (PI. 3), normal
secondary layer fibres are bent sharply backwards against a line, posteriorly inclined,
and running from the primary/secondary layer interface inwards towards the shell
interior. Below this line, a series of lamellae, composed of primary shell material,
are stacked one below the other so that their posterior ends are in continuity with the
line of 'unconformity'. The lamellae are flat or slightly convex inwards and vary
between 5 /mi and 10 /mi in thickness. Finally the lamellae pass inwards to a
normal primary and secondary layer succession which extends anteriorly to the next
major concentric growth line. Secondary layer fibres associated with major over-
lapping shell units are generally stacked with long axes parallel, and not at right
angles, to the valve margins.
The frequency and spacing of the microscopic concentric growth lines suggest that
they are remnants of the linear junctions between successive rows of outer epithelial
cells as each in turn changed over from organic to mineral secretion. The slight
flexures in the shell layers are produced by a change from radial to tangential growth
which results in the radial growth vector being reduced to zero, whilst the growth
vector normal to the shell edge is greatly increased. Calcite secretion does not stop
and there is no retraction of the mantle, but the fibres located around the periphery
of the shell tend to grow parallel and not at right angles to the shell edge. The
major overlapping shell units which are found around the periphery of most mature
individuals appear similar to the free growth lamellae of Krans (1965 : 88). When
SHELL STRUCTURE
a.
d.
FIG. 3. a-c. Stylized drawings of transverse sections through secondary layer fibres
showing how a series of slight changes in profile may produce a substantial overall
displacement, d. Section through an outer epithelial cell showing how a lateral con-
traction will produce greater concavity in the secreting plasmalemma.
examined in greater detail, however, they are found to be the culmination of a series
of minor mantle readjustments. The first stage in the formation of a new shell unit
around the edge is brought about by a breakdown in the secretory regime of the
underlying outer epithelium. This may be preceded by a slight posterior withdrawal
of the outer mantle lobe, giving rise to a narrow zone of fibres which are bent round
sharply on one another. It is remarkable how the gradual change in shape of a cell,
and in particular its secreting plasmalemma, when combined with similar changes in
adjacent cells, can give rise to macroscopic variations in the shell layers. A lateral
contraction produces greater concavity in the secreting plasmalemma, hence the
terminal face of the fibre secreted by it will become narrower and more highly convex
(Text-fig. 3). The gross effect is to produce a lateral foreshortening and vertical
thickening within the shell layer. The first major break in the secretory regime of
the outer epithelium corresponds to a halt in the 'conveyor belt' system of cell
proliferation and hence to a lapse in radial growth. Deposition continues normal to
the plane of regression but the organic membranes secreted by arcuate strips of each
outer epithelial cell are often pinched out. A gradual regression of the mantle
edge follows with deposition of successive horizontal lamellae composed of primary
shell. The lamellae are not stacked vertically one above the other, but are stepped
progressively backwards. Between each regression plane there is a thin wedge of
micritic material. Very probably the interlamellar spaces were occupied by organic
material secreted by the mantle to assist in its backward slide. On the other hand,
if deposition of periostracum were continuous at the mantle edge (as is highly likely)
the spaces between the lamellae may have been occupied by folds of that protective
outer cover which would have functioned as an ideal seeding sheet for each consecutive
calcite lamina.
SPIRIFERIDE BRACHIOPODA 201
To produce a thickening of the shell in this manner, it is clear that the same outer
epithelial cells must have undergone cyclical changes in secretory regime (Text-fig. 4) .
Initially involved in secreting the primary, then secondary, shell layers, they must
have continually fluctuated between organic and inorganic episodes of deposition
until the stage was reached where mantle retraction stopped and normal growth of the
shell layers resumed.
(e) Muscle attachment areas
The areas of muscle attachment in Spiriferina are distributed similarly to those
found in living articulates, except for the ventral adductor muscle fields which are
situated on both sides of a large, pointed, ventral, median septum and not on the
floor of the valve.
(i) Pedicle valve
The ventral diductor and adjuster muscle bases leave strong impressions on the
valve floor, so that the ventral muscle scars are well defined (PI. 2, fig. 4) . Around the
anterior margins of each scar, there is a prominent, anteriorly arcuate ridge (PI. 2,
fig. 4 ; PI. 4, fig. i) like that found around the anterior border of the ventral muscle
scars of the Recent rhynchonellide Notosaria nigricans (Sowerby). It is built up
from secondary layer fibres. Although the effects of fossilization tend to obscure
the finer details of textural variations in the shell fabric, it is evident that the
exposed parts of fibres on the posterior facing side of the ridge exhibit longer, more
ragged trails than those comprising the crest of the ridge. Traced posteriorly from
the ridge crest the exposed fibre trails are overlapped by fibres whose terminal faces
exhibit a fairly well-developed mosaic pattern. The difference in growth direction
of both sets of fibres is striking, which suggests that the zone of fibres overlapping
the ridge grew quite independently of those which actually composed the ridge. In-
deed, a significant lowering of the level of the valve floor behind the ridge and the
existence of long, ragged, exposed trails on its posteriorly sloping side suggest that
the outer epithelium in contact with that part of the ridge was resorbing and not
depositing shell material. About 500 ju,m behind the ridge, the inner shell surface
is cut up by a series of deeply impressed furrows, each measuring between 75-100 pm
in width (PI. 4, fig. 2). Within the ventral adjuster muscle field, the furrows run
longitudinally and are generally separated from one another by narrow ridges of
fibres exhibiting a fairly well-developed secondary shell mosaic (PL 4, fig. 3) . Within
the diductor muscle field, however, the anterior parts of the furrows bend round to
face the median septum. In addition, groups of neighbouring furrows tend to merge
together, unlike the adjuster scar, so that the outlines of the impressions appear
flabellate.
The occurrence of a well-developed mosaic pattern within a muscle scar is unusual
and has not been observed within the muscle scars of any Recent articulate. Gen-
erally a myotest shell fabric is quite distinct from the normal secondary shell mosaic
pattern. The fact that fibres occurring within the elongate furrows of the muscle
SHELL STRUCTURE
a. Halt in radial growth : deposition
continues normal to inner shell
surface with pinching out of organic
membranes between secondary
layer fibres
Halt in calcite deposition : mantle
edge reverts to wholly organic
secretion
(outer epithelium omitted for clarity)
Calcite deposition restored over
slightly wider strip of shell edge
organic layer may comprise
folded periostracum
Deposition of alternating organic
and inorganic layers affecting
increasingly wider area of shell
edge
Succession of overlapping
organic and inorganic laminae
succeeded by normal primary
and secondary shell deposition
FIG. 4. a-e. Diagrammatic sections to illustrate the formation of a major overlapping
shell unit by progressive mantle retractions at a valve margin of Spiriferina (p/o -
periostracum, p.l - primary layer, s.l - secondary layer, o.e - outer epithelium).
SPIRIFERIDE BRACHIOPODA 203
scar are considerably more irregular in outline suggests that the terminal parts of the
muscle base, which overlay the associated outer epithelium responsible for secreting
myotest, were not evenly distributed. Since the presence of muscles in the vicinity
of outer epithelial cells in Recent Brachiopoda has been shown to promote the forma-
tion of tonofibrils within each cell body, as well as drastically affecting its secretory
behaviour (Williams ig68a : 14), it is reasonable to assume that the outer epithelial
cells underlying the muscle bases of Spiriferina must have been similarly affected.
The linear arrangement of the furrows within the ventral muscle field of Spiriferina
is consistent with an overlying muscle base which has been segregated into distinct
bundles of contractile tissue. Since the furrows, in general, run parallel to the median
plane, as do the corrugated grooves on the cardinal process, it is reasonable to assume
that the sheet-like bundles of muscle tissue must have run lengthwise in the same
direction.
The ventral adductor scars are large in comparison with those of Recent Rhyn-
chonellida and Terebratulida. They are impressed upon both sides of the median
septum and consist of a number of furrows which run dorso-ventrally. These furrows
are similar to the ones occupying the adjuster and diductor scars and represent the
areas of emplacement of the terminal parts of the ventral adductor muscle bases.
The median septum is built up of secondary layer fibres, where, in general, the fibres
grow from base to apex. Within the dorso-ventrally aligned furrows, however, the
shell structure is more irregular and typical of a myotest shell fabric. The contrast
between modified and standard secondary layer fibres is well seen in transverse
sections through the median septum where the myotest stands out as a zone of small,
gnarled, irregularly stacked fibres which lies sandwiched between two layers of more
orthodoxly stacked fibres (PI. 4, figs. 4, 5). The stacking is most unorthodox and
there is evidence of fusion of adjacent trails.
Growth of the ventral median septum takes place by the addition of secondary
shell material along its anterior facing edge. As the septum expands in size, how-
ever, its posterior, earlier-formed parts are gradually overlapped by more secondary
shell material deposited subsequently in the umbonal region. This later deposit
spreads evenly over the older shell surface and so produces what appears, in trans-
verse section, to be a sharp line of unconformity (PL 4, fig. 6).
Around the posterior ends of the ventral adjuster and diductor scars the muscle
impressions are very deep. Behind the muscle scars, the shell is considerably
thickened by an overlapping accumulation of secondary layer fibres which piled up
behind the muscle base. In this area, although some groups of fibres grow anteriorly
and antero-laterally, the great majority appear to be directed posteriorly. In radial
section, fibres around the posterior part of the muscle scars, showing good cross-
sectional outlines, are seen suddenly to change growth directions.
(ii) Brachial valve
The quadripartite dorsal adductor scars are situated symmetrically on both sides
of a slight median rise, with the anterior pair more closely spaced together than the
posterior pair. Viewed at low magnifications, the surface textures of the scars are
distinctive and unlike those of the ventral scars. The surface topography of the
16
204
socket
interarea
SHELL STRUCTURE
cardinal process
inner socket ridge
adjuster scar
crural base overlapping
resorbed inner face of
spiral lamella
FIG. 5. Stylized drawing of the cardinalia of Spiriferina showing the growth vectors of
the regular mosaic and the distribution of resorbed (stippled) irregular mosaic.
anterior scars is undulating with puncta occupying hollows between irregularly
distributed mounds (PI. 5, fig. i). The surface of the posterior scar is, on the other
hand, relatively flat. However, both sets of scars appear to be coated with a micritic
crust so that the detailed shell ultrastructure cannot readily be discerned. On some
parts of the surface, where the sedimentary coating is thin, it would appear that the
under-surface is fibrous. However, the skeletal fabric is certainly unusual, for on
broken parts of the shell myotest deposits bear little resemblance to the smooth
regular outlines of fibres comprising the underlying shell succession (PL 5, fig. 2).
The cardinal process and the dorsal adjuster muscle scars are situated close to one
another in the umbonal region of the brachial valve (Text-fig. 5) . The striate cardinal
process of Spiriferina closely resembles that of the terebratellacean Terebratalia
transversa (Sowerby), in that it comprises a series of radially disposed, corrugated
ridges, between 50 /mi and 100 /x,m wide, made up of tightly interlocking secondary
layer fibres (PL 5, fig. 3). The ridges extend from the posterior shell edge to ter-
minate anteriorly as a series of buttresses which rise steeply from the valve floor.
Antero-lateral to the cardinal process lie the dorsal adjuster scars which are inserted
upon the crural bases. Both the cardinal process and each dorsal adjuster scar are
themselves enclosed postero-laterally by an inner socket ridge. The adjuster scars
are very deeply impressed upon the shell and, within each scar, a number of narrow
stalks composed of secondary shell material project posteriorly at a low angle to-
wards the umbo (PL 5, fig. 4). Since the surrounding parts of the shell surface are at
SPIRIFERIDE BRACHIOPODA 205
a much higher level than that within the scars, it is obvious that the deep impressions
of the adjuster scars have been fashioned as a result of strong resorption by the over-
lying outer epithelial cells which were attached to both dorsal adjuster muscle bases.
The narrow stalks protruding from the floor of each scar are therefore not outgrowths
of the shell. They are merely remnants of earlier-formed parts of the shell succession
which have escaped resorption.
(iii) Functional considerations
In examining the surface topographies as well as the shell ultrastructure within the
areas of muscle attachment in Spiriferina, some attempt has been made to reconstruct
the morphology and disposition of its muscle system. The longitudinal 'striation'
of the cardinal process and the flabellate pattern of the ventral diductor scars suggest
that the diductor muscle fibres were segregated into a number of discrete bundles or
sheets whose bases were accommodated within the various depressions of the shell.
If the curiously ridged topography of the anterior dorsal adductor scars can be taken
as a guide to the nature of the contractile tissue associated with them, then it seems
likely that the adductor muscles consisted of a large number of spindle-shaped
strands. Each strand was composed of a number of muscle fibres and corresponded
to a ridge or hollow on the surface of the scar. However, it is possible that the pos-
terior adductor muscles, like those in a number of Recent articulates (Rudwick
1961 : 1021), were striated. A variation in muscle composition between anterior
and posterior adductors might explain the observed differences in surface texture
within each pair of scars.
The close proximity of the inner arms of the spiralia and its transverse support, the
jugum joining the distal ends of the crura, must have restricted the passage and
emplacement of the muscle systems in Spiriferina to within relatively narrow limits.
However, the size and distribution of the scars points to Spiriferina having had a
rather strong and efficient muscle system. Mechanically it can be shown that muscles
situated closest to the median line are most effective, since it is in such a position
that the greatest proportion of the force is used either to open or to close the shell
(Armstrong igGSb : 646).
Comparison of the myotest ultrastructures of Spiriferina with those of living bra-
chiopods is not easy, for the muscle scar surfaces on which modified mosaic patterns
might be displayed are usually badly affected by diagenesis. Either the surface
may be covered by a thin micritic layer (as in the dorsal adductor scars) or, when this
coating has been removed, the skeletal fabric may appear cracked and pitted (as in
the ventral diductor scars). Since terminal faces located well outside the muscle
scars of many other fossil genera, as well as Spiriferina, are found to be similarly
affected, the existence of such ultrastructural irregularities on fibres incorporated
within the muscle scars cannot be taken for certain as characteristic of any myotest
shell fabric. Even though the detailed morphology of myotest fibres is obscured
on the shell surface, some idea as to their overall shape and stacking can be obtained
from a study of appropriately sliced radial and transverse sections. On carefully
etched surfaces, the myotest fibres can be picked out readily on account of their
distinctive size, shape and stacking.
206 SHELL STRUCTURE
(f) The brachidium
The brachidial apparatus of Spiriferina consists of a pair of calcareous spires which
extend from the distal ends of the crura and are drawn out laterally away from the
median plane. When viewed along the axis of coiling from base to apex, the left-
hand spire is coiled clockwise and vice-versa for the right-hand spire. Just anterior
to the distal ends of the crura, the innermost lamellae of each spire are connected by
a curved jugum which is flattened dorso-ventrally (Text-fig. 6).
C
FIG. 6. View of the spiral brachidium of Spiriferina walcotti (Sowerby).
Davidson (1852 : 23-24) has given an accurate description of the spires belonging
to the closely related species Spiriferina rostrata (Schlotheim) which possesses a
spiral brachidium virtually identical to that found in S. walcotti. In describing the
shape of a lamella, Davidson notes that it 'is neither smooth nor of equal thickness
on all its width, differing on each side and variable, but always thicker on the inner
side of the circumference than on the other which tapers out into an acute edge, and
. . . the thickest part of the spire is towards its middle, where it forms a circular
elevation, diminishing again towards the outer edge'.
As will be shown, the attitude and outline of the lamellae are important clues to
the relationship between lophophore and spiralia. In this study, no set of spires
completely free from matrix was available and observations were carried out on
carefully selected horizontal and vertical transverse sections of intact spiralia en-
tombed in rock matrix. However, a few fragments were extracted manually, so
that it was possible to examine localized parts of the surface mosaic.
The spires are composed of secondary layer fibres which exhibit a distinctive and
well-defined pattern of growth. Trails of fibres, exposed on the freshly broken
surfaces of fragmentary pieces of spiral lamellae, are found to follow a crescentic
path, convex towards the exterior, which runs from the inner to the outer edge of the
SPIRIFERIDE BRACHIOPODA
207
a. b.
FIG. 7. a. Fragment of a spiral lamella showing the anterior projection of fine spines from
the median-facing side. The orientation of fibre trails is shown by growth vectors,
b. Schematic diagram of part of a spiral lamella showing the direction of growth of fibres.
A mosaic is developed on both sides of the lamella so that, in section, fibres appear to
arch outwards in both directions from a median plane. In sections through the inner-
most whorls, as shown here, a thin layer of non-fibrous calcite (stippled) is interposed
between the two sets of fibres and is continuous with spine bases. The blunt inner edge
of the lamella is undergoing constant resorption.
lamellae (Text-fig. 7a, b). In Spiriferina, shell deposition occurs on both the apical
side (facing towards the apex of the spiralium) and basal side (facing towards the base
of the spiralium) of the lamellae, so that in transverse cross-sections the convex faces
of fibres are seen to arch outwards in both directions from a median plane. In effect,
the path followed by each outer epithelial cell responsible for secreting the spiralia
appears to be that of an equiangular (or logarithmic) spiral (Text-fig. 8). As the
spiralium increases in size, the outer epithelial cells gradually migrate around the
lamellae and so contribute to the growth of parts of the spiralium which are pro-
gressively more distant from its apex. In addition, if a tangential cut is made on a
spiral lamella, the observed overlapping disposition of the long axes of secondary
layer fibres (Text-fig. 9) indicates that, for the spiral lamella to expand continuously
to fill the brachial cavity, new cells (and hence new fibres) must be proliferated
continuously in a linear generative zone along the sharp leading edge of the lamella.
On certain parts of the spiralia there are surfaces of resorption. An area of re-
sorption is readily recognized by the absence of a surface mosaic which is usually
replaced by long exposed trails of fibres possessing no recognizable terminal faces.
In transverse cross section, provided the surface of resorption is not coplanar with
a growth surface, the distinction is clear-cut. The distinctive mode of stacking of
2o8 SHELL STRUCTURE
fibres provides a convenient 'way-up criterion' (Williams ig68a. : 8). The profile of
the keel, which is convex towards the growing surface, serves to indicate the precise
attitude of the depositional surface in that part of the shell at that moment in time.
If groups of fibres, stacked in rows one above the other, are truncated by the existing
surface profile, then resorption must have taken place.
r
FIG. 8. Reconstruction of the growth path of a single fibre contributing to the growth of a
spiral lamella. Only a small segment of the spiral is present at any one time since the
inner edge of a lamella is constantly being resorbed.
Around the blunt inner edges of the lamellae fibres are resorbed. Some resorption
also occurs on the basal sides of lamellae, especially on the posterior facing halves of
the spires. Towards the dorsal and ventral extremities of each lamella, the zone of
resorption gradually decreases until practically all outer epithelial cells on the basal
side are actively secreting. As previously mentioned, the outer epithelial cells
responsible for secreting each spiralium continually migrate backwards along the
curved lamellae towards the median plane. This process does not continue in-
definitely, however, for on the dorsal surface of the innermost lamellae of both
spiralia, lateral to the jugum, resorption takes place.
On the anterior facing parts of the lamellae a considerable number of small spines
project outwards at an oblique angle (Text-fig, ya, b). As a rule, the spines always
project from the basal sides of the lamellae whilst on the apical side the surface is
devoid of any unusual outgrowths. Structurally they resemble the calcareous rods
(taleolae) which permeate the shells of Plectambonitacea such as Sowerbyella
(Williams 1970 : 339), in that the secondary layer fibres, deflected around the
obliquely inclined cylindroid bodies, arch outwards towards their distal extremities.
If the anterior facing part of a spiral lamella which bears the spinose projections is
sectioned horizontally, the mode of formation of the spines becomes apparent from
an examination of the newly exposed shell succession. Such sections of the inner-
most whorls of the spiralia expose a thin layer of non-fibrous calcite, about 10 /am
wide, which runs from the blunt inner edge to the sharp outer edge of each lamella
SPIRIFERIDE BRACHIOPODA
209
FIG. 9. Lateral view of a spire of Spiriferina showing lines of tangential section and the
growth direction of fibres. In the anterior section (i), fibres diverge upwards from a
median plane whereas in the posterior section (2), the fibres diverge downwards.
(Text-fig. 7b). At infrequent intervals, cylindroid bodies up to 60 /u.m in diameter
swell out from this layer (on only the basal side of the lamella) and cause the sur-
rounding secondary layer fibres to be deflected around them on all sides. Judging
from the morphological differences between spines and fibres, and the sharpness of
boundaries between them, there is every indication that each was deposited by a
different type of cell. The manner in which the bases of spines are submerged in
secondary layer fibres points to each spine having first been secreted by a small tubular
evagination of specialized epithelium situated around the sharp, outer edge of the
spiral lamella. As the diameter of each spiral whorl increased, the bases of spines
were gradually overlapped by successive secondary layer fibres until finally they
became engulfed in the resorbing epithelium situated at the blunt inner edge of the
lamella. As well as forming the cores of the innermost whorls of the spiralia, the
homogeneous calcite layer is also present within the jugum where it forms a promi-
nent inner layer in transverse section. On the outer whorls of the spiralia, however,
the layer is no longer present but spine bases continue to disrupt the shell succession.
Evidently the specialized epithelium which gave rise to the subsidiary layer occupied
the outer edges of the innermost spiralia and the jugum, but on the outer whorls was
concentrated only in small circumgenerative zones which gave rise to isolated
spinose outgrowths that did not otherwise affect the shell succession. The fact that
the spines are situated only on that part of the spiralia facing the commissure tends
to suggest that they may have served some protective function. The spines may
have acted either as a prickly deterrent to predators seeking to devour the soft parts
of the animal, or as a grille preventing coarse particles of sediment from entering the
brachial cavity (assuming a lophophore current system which filtered food and water
inwards through the arms of the spiralia).
2io SHELL STRUCTURE
(g) Articulation
The articulation provided by the teeth and sockets of Spiriferina is highly effective.
Each is composed of secondary layer fibres, and by plotting the long axes of exposed
trails as growth vectors, growth maps can be constructed for both structures. Since
each fibre is a record of the path taken by each corresponding outer epithelial cell,
growth maps can be used to interpret the nature of the build-up of both exoskeletal
outgrowths in terms of bulk epithelial movements.
The dental sockets extend along the inner margins of the notothyrium from the
umbo to the hingeline. On the median-facing side, each socket is bounded by a
stout inner socket ridge whilst the overhanging edge of the interarea functions as an
outer socket ridge (Text-fig. 5). Each socket can be divided into two regions with
the anterior part forming a much deeper depression than the posterior part. In the
anterior part, which accomodates the distal end of the tooth, the fibres grew across
the socket from the overhanging edge of the interarea towards the inner socket ridge.
In the posterior part, which was no longer involved in articulation and does not now
come into contact with the point of the tooth, the fibres grew along the floor of the
socket from the umbo outwards. As the outer surface of the dorsal interarea is
composed of primary shell material, the directions of growth of the underlying secon-
dary layer fibres are normally obscured. However, in specimens where the primary
layer has been removed, the secondary layer fibres are seen to be directed outwards
from the umbo parallel to the edge of the notothyrium.
The teeth and dental plates stand out as prominent features in the umbonal region
of the pedicle valve. As well as functioning as part of the hinge mechanism, lateral
outgrowths of the teeth also serve to restrict partially the triangular delthyrial
opening. What appear, at first sight, to be a pair of disjunct deltidial plates are
structures composed solely of secondary shell material. Each structure arises from
that part of the tooth bordering the delthyrium and is fashioned into a laterally
projecting ridge which runs from the apex of the delthyrium to the hinge line (Text-
fig. 10). As similar ridged outgrowths of the teeth have been found bordering the
delthyrium of Spirifer trigonalis (Dunlop 1962 : 491) and given the name dental
ridges, it seems reasonable to apply the same terminology to the corresponding
ridges in Spiriferina. The fibres comprising each dental ridge in Spiriferina grew
along the length of the ridge from the delthyrial apex to the hinge line. Over the
greater part of each tooth, fibres grew towards the distal end. However, on the side
facing into the delthyrial cavity the pattern is more complex.
From the hinge line, part of the shell swells into a large bulbous ridge which is
situated on the median-facing side of the tooth and just inside the dental ridge
(PI. 6, fig. i ; Text-fig. 10). This unusual outgrowth, which has been observed in
every specimen so far examined, cannot be involved in articulation as it is situated
on the opposite side of the hinge line from the distal end of the tooth. At its widest
part the ridge is flattened and appears abraded. This observation is confirmed by a
closer inspection of the surface which shows the exposed parts of fibres comprising
that part of the ridge to be ragged and misshapen (PI. 6, fig. 2). Due to the absence
of any exoskeletal outgrowths on the brachial valve in the immediate vicinity, which
SPIRIFERIDE BRACHIOPODA
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212 SHELL STRUCTURE
as a result of rubbing against the ridge could have given rise to such a shell fabric,
it seems likely that the abrasion must have been caused by pressure and possible
movement around the proximal end of the pedicle.
Both teeth fit snugly into the sockets of the brachial valve, but despite having to
grow in a partially confined space, the distal extremities are still the main areas of
growth on the teeth. In radial section, the cross-sectional outlines of fibres compris-
ing the distal ends of the teeth show a rhythmic variation in direction of growth
(PI. 6, figs. 3, 4). At the point of the tooth the epithelium appeared to move in four
consecutive directions - dorsally, laterally, ventrally, laterally - and then the se-
quence is repeated. If the two lateral movements of the cycle were in opposing
directions, as seems likely, then the motion would be helical.
IV. SHELL STRUCTURE OF OTHER SPIRIFERIDA
(a) Atrypidina
According to Boucot et al. (1965 : H632), the Atrypidina are divided into two super-
families based on the attitude of the spiralia. The Atrypacea bear spiralia with
apices directed medially or dorso-medially, whereas the spiralia of the Dayiacea are
directed laterally or ventrally. From an evolutionary standpoint, the Atrypidina
are important since they include the earliest forms of spire-bearing brachiopods.
Cooper (1956 : 136) cites a small undescribed form from the Row Park Formation of
Maryland and another, possibly the same species, from the Crown Point Formation
of New York (both Middle Ordovician) as stratigraphically the oldest yet recorded,
but interior details of neither are known. They both appear to have ' Protozyga-like'
shells, and on this basis Cooper regards the slightly younger Protozyga s.s. as the most
primitive of all Spiriferida. By late Ordovician times several stocks of spire-bearing
brachiopods had become established. These include the small costate or multiplicate
atrypaceans Protozyga, Zygospira, Hallina and Catazyga.
(i) Atrypacea
Though impunctate, the calcareous shell succession of Protozyga elongata Cooper
from the Lower Bromide Formation (Upper Ordovician) of Oklahoma is broadly
comparable with that of Spiriferina walcotti (Sowerby) . P. elongata is small, seldom
more than 5 mm in length, and thin-shelled. Its primary layer, measuring up to
10 /u,m in thickness, is composed of narrow crystallites with long axes disposed normal
to the isotopic primary/secondary layer boundary. The secondary layer is also
comparatively thin and has not been found to exceed 50 /i,m. Transverse sections
across the widest part of the shell reveal a succession of small, flattened fibres which
although irregular in profile are stacked in a very compact fashion (PI. 6, fig. 5).
Close to the valve margins fibres measure between 4 //,m >and 6 //.m in width, but
towards the postero-median regions of the same specimen lateral boundaries of
individual fibres tend to amalgamate and produce a more massive skeletal fabric.
In view of the irregular nature of the remainder of the skeletal succession, which may
in any case have been diagenetically induced, it would be hazardous to guess as to
SPIRIFERIDE BRACHIOPODA 213
the physiological significance of such a variation in fabric. However, if the overall
irregularity in fibre profile is a primary feature, then the welding together of adjacent
parts of fibres may reflect deposition by outer epithelial cells whose normal secretory
processes were disrupted due to the encroachment of a muscle base. Were it not that
Protozyga possessed a rudimentary spiralium of generally less than one convolution,
it might easily be mistaken for a small, mildly plicate rhynchonellid.
Compared with Protozyga, Zygospira is further advanced along the spiriferid line
of descent, in that it possesses a more fully developed spiralium of up to four con-
volutions with apices directed medially. Specimens of Zygospira modesta (Say),
collected from beds assigned to the Richmond Group (Upper Ordovician) exposed
near Nashville, Tennessee, reveal a secondary shell fabric which is more regular than
that of Protozyga elongata. Although the shell exterior of Zygospira is markedly
costate, the undulations of the costae are not preserved on the inner surface of the
valves. When traced any great distance from the shell margins, the secondary layer
fibres tend to fill out and eliminate the undulations so that both valves are thickened
below the ribs and correspondingly reduced below the intervening grooves. Cross-
sectional outlines of mature secondary layer fibres generally conform to a flattened
diamond shape and measure about 10 /mi to 12 /mi in width (PL 6, fig. 6). As shown
below, the outlines of sectioned secondary fibres are important in providing a means
of deducing the pattern of the internal secondary shell mosaic. On this basis, the
terminal faces of Zygospira are clearly rhomb-shaped (as opposed to smoothly curved
in Spiriferina) with the longer diagonal of each rhombohedron coincident with the
long axis of each corresponding fibre trail. The regular diamond-shaped outlines of
fibres, though present over the greater part of both valves, are disrupted within the
vicinity of the dorsal and ventral muscle scars ; but such localized modifications in
the secretory regime do not lead to any great thickening of the shell succession in
either valve.
In the related Catazyga headi Billings from the Richmond Group of Adana County,
near Winchester, Ohio, the pedicle valve in particular is greatly thickened around its
posterior regions. Anteriorly the shell thickening is confined to a median platform,
probably a muscle platform, but towards the umbonal region deposition becomes
more pronounced in the areas laterally adjacent to the scars. As a result of this
postero-lateral shift in the main zone of calcification the level of the ventral muscle
scar surface changes from being an area which anteriorly was above that of the
surrounding floor to that of a deep impression. In cross-section, a primary layer
about 20 /am thick is succeeded by secondary layer fibres which are diamond-shaped,
like those of Zygospira (PL 7, fig. i). Fibres comprising the lateral and anterior
regions of both valves usually measure between 10 /mi and 12 /mi in width, but away
from the margins there is an increase in fibre size with widths of 20 /mi to 25 /mi
becoming common. Within the areas of maximum shell deposition, the secondary
fibres give way to a coarse tertiary prismatic layer (PL 7, fig. 2). Compared with the
uniformly stacked 'columns' of the Recent terebratulide Gryphus vitreus (Born)
(MacKinnon iQ7ib : 41), the tertiary layer of Catazyga is rather irregular. This is
due mainly to the impersistent nature of adjacent crystal boundaries which, though
generally aligned normal to the inner shell surface in true 'prismatic' fashion, tend
214 SHELL STRUCTURE
to migrate laterally from time to time. The whole of the tertiary layer appears to
take on a 'jigsaw-puzzle' type of shell fabric which is considered to be transitional
between that of an orthodoxly stacked secondary layer and the more conventional
'columnar' tertiary layering which is typical of certain later spiriferide genera. In
places, the prismatic shell material gives way both laterally and vertically to normal
fibrous outlines, so that the outer epithelial cells responsible for secreting the tertiary
layer were obviously capable of reverting to secondary shell deposition. The
probability is high that such a distinctive tertiary layer fabric is original, for gently
etched sections of Catazyga are, in places, traversed by a fine depositional banding.
The banding, which persists across numerous adjacent crystalline boundaries, is
similar to that found in sections of living Gryphus.
Around the shell margins of Catazyga there is evidence that the mantle became
detached periodically or, at least, reverted to primary shell deposition. From a
point near the outer shell edge, a wedge of primary shell material, about 35 /mi at
maximum thickness, dips posteriorly inwards to terminate a short distance from the
inner shell surface (PI. 7, fig. 3). This wedge is bounded on either side by orthodoxly
stacked secondary layer fibres. Unlike similar wedges occurring in some Recent
Brachiopoda, the primary shell material is not massive but is composed of a series
of regularly stacked crystallites between 8 //,m and 12 jam in width which stand at
right angles to the earlier-formed parts of the secondary shell succession. As the
boundaries between primary and secondary deposits are indistinct, it is not known
for certain whether a clear break in deposition did occur before the changeover.
However, if the fabric of the primary shell wedge is original, it is possible that organic
membranes, continuous with those in the preceding secondary layer, ensheathed the
primary layer crystallites. For such to be the case would not require complete
mantle detachment, but merely a temporary reversal from secondary to primary
shell deposition.
Contemporaneous with the ribbed zygospirid stock, but less common, are certain
smooth-shelled Atrypacea, including Idiospira, which are assigned to the family
Lissatrypidae. In transverse sections of Idiospira thomsoni (Davidson), from the
Craighead Limestones (Caradoc) of the Girvan district, the outlines of secondary layer
fibres are variable. Some sections show neatly stacked fibres with smooth curved
outlines (PI. 7, fig. 4), which contrast with the sharp, angular outlines of fibres
comprising the shells of Zygospira and Catazyga, whereas other parts of the shell
succession (PI. 7, fig. 5), exhibit irregular outlines which resemble those oiProtozyga.
Judging from the way in which, in Idiospira, these fibres with smooth symmetrical
outlines are seen to merge with neighbouring groups of irregularly stacked fibres, it
seems highly likely that the latter are the product of secondary recrystallization
across adjacent fibre boundaries. If this is the case, then the original secondary shell
mosaic of Idiospira consisted of alternating rows of smooth spatulate terminal faces
and not diamond-shaped outlines as in other Atrypacea. No tertiary layer has been
found in Idiospira.
In Silurian and Devonian Atrypacea the external (and internal) morphology of
both valves became highly diverse, yet much of this variety of form can be rational-
ized into two main components. These are a radial pattern of ribs and a concentric
SPIRIFERIDE BRACHIOPODA 215
pattern of overlapping growth lamellae (Copper 1967 : 123) ; both components are
usually built up from primary and secondary shell material. Complete specimens of
five Siluro-Devonian forms were available for study. These were Atrypa reticularis
(Linne) from the Wenlock Limestone of Shropshire, Atrypa sp. from the Upper
Hamilton Group (Middle Devonian) of New York, Atrypina hami Amsden from the
Haragan Formation (Lower Devonian) at White Mound, Murray County, Oklahoma,
Spinatrypa sp. from the Hackberry Stage (Upper Devonian) of Rockford, Iowa, and
Desquamatia subzonata Biernat from the Givetian shales of Skaly in the Holy Cross
Mountains, Poland.
In all five stocks, the primary layer is well developed and usually attains a
maximum thickness of up to 40 /mi below the rims of overlapping growth lamellae
where it is best protected from abrasion. As well as revealing a porous texture,
sections of this thin outer layer (e.g. PL 7, fig. 6) show it to be traversed by a fine
lineation which is orientated either at a steep inclination or normal to the outer shell
surface.
The shape and stacking of secondary layer fibres are also remarkably uniform and
compare well with those of Catazyga and Zygospira (but not Idiospira). In sections
of the Middle Devonian species of Atrypa the outlines of secondary layer fibres are
well defined (PL 8, fig. i). Diamond-shaped profiles of sectioned fibres which
measure, on average, about 25 p,m in width are characteristic not only of this genus
but also of all other representatives examined. Since even the early zygospirid
stocks exhibit similar fibre outlines, it seems reasonable to assume that this feature
was common to the family Atrypidae as a whole. In this respect, representatives of
the Lissatrypidae (the smooth-shelled Atrypacea) have still to be investigated.
Copper (1967 : 127) has examined optically the shell structure of a number of
Devonian Atrypacea by means of cellulose acetate peels. In more 'advanced' and
'complex' atrypids like Gruenewaldtia, Mimatrypa, Spinatrypa and Atryparia, he
reports that secondary layer fibres are consistently larger than those of other related
genera.
At regular intervals in the shell succession, groups of secondary layer fibres are
outwardly deflected towards the primary layer in a manner reminiscent of punctation,
but at the centre of such deflections no hollow canals are found. Instead, the clear-
cut diamond-shaped outlines of fibres degenerate into a central nucleus of irregularly
interwoven accretions (PL 8, fig. 2) which resemble in appearance the myotest shell
fabric of certain living articulates, such as Notosaria. Since the outer epithelial
cells responsible for the deposition of the latter are known to be permeated by dense
concentrations of tonofibrils associated with muscle attachment, it is reasonable to
assume that the cells responsible for the outward deflections of the Atrypa shell must
have been affected to a similar degree. Over the greater part of the inner shell surface,
excluding muscle areas and exoskeletal outgrowths, these outward deflections of the
secondary layer find expression as a series of pits which have been recognized, in the
past, as gonadal markings (PL 8, fig. 3). Presumably the gonads were attached to the
outer epithelium and caused it to bulge outwards at points represented by the pitting
on the shell surface. Modifications in the shell surface can thus be attributed to a
breakdown in the normal processes of deposition such as are found under muscle
216 SHELL STRUCTURE
attachment areas with a localized spread in the organic secretory phase and a cor-
responding reduction in mineral exudation.
The concentric overlapping growth lamellae adorning the surfaces of so many
Atrypacea were deposited by the marginal parts of both mantle lobes, which were
subject to periodic fluctuations in secretory behaviour (PI. 8, figs. 4, 5) . Both primary
and secondary shell layers are affected but not in the manner described for Spiri-
ferina. The structural relationships between overlapping shell units are, however,
closely comparable with those described for Recent articulates by Brunton (1969 : 192)
and Williams (i97ia : 61). Each planar surface, along which the normal sequence of
shell deposition was interrupted, dips posteriorly at a low angle towards the shell
interior. In all genera examined, such regression planes invariably interrupt the
secondary shell succession and none was found which could be considered to have
affected only the primary layer. Sandwiched between the regression plane and the
immediately younger parts of the shell succession is a wedge of primary shell material
which thins posteriorly. Where the wedge thins out, the regression plane is marked
by a narrow zone of sharply flexed fibres which can be traced running posteriorly for a
short distance before becoming lost in the remainder of the secondary shell succession.
In the coarsely plicate form Spinatrypa, tubular prolongations of the ribs extend
outwards from the inner edge of each prominent overlapping growth lamella. The
spines grew in such a way that their development was complete before the onset of
the succeeding mantle regression. Initially a spine was merely a gently curved
extension of a rib-crest but gradually, due to peripheral accretion, the opposing edges
grew round towards one another and met on the underside (Text-fig, n). Where the
two edges have come together a seam is preserved. The spines are built up from
primary and secondary shell material.
Since each concentric row of spines is succeeded by a plane of regression, it is
evident that no sooner had a row of spines grown to maturity than its outer epithelial
lining became detached due to mantle retraction. If the regression was slow, the
inner surfaces of spines may have been covered by a periostracal deposit, but in any
case they could not have been functional for any length of time. With the onset of
shell deposition after the mantle regression the base of the spine was overlapped by
subsequent primary and secondary shell layers so that no further contact with the
mantle was possible.
In addition to possessing a well-developed primary and secondary shell succession,
Silurian and Devonian Atrypidae are characterized by an inner tertiary layer deposit
which may be massive or interdigitate with parts of the secondary layer (PI. 8, fig. 6).
The tertiary layer attains maximum thickness in the postero-median region of both
valves, but around the valve margins only primary and secondary shell deposition
occurs. The nature of the tertiary layer is variable, even within a single specimen,
and may either consist of a series of vertically disposed crystals with well-defined
boundaries or be massive. When clear-cut crystal boundaries are present they are
commonly in structural continuity with the outlines of underlying secondary layer
fibres.
Tertiary layer deposits are also found within muscle scars. In Atrypa, the areas
of muscle attachment are deeply impressed on the inner surfaces of both valves. In
SPIRIFERIDE BRACHIOPODA
217
FIG. ii. a-d. Progressive stages in the formation of a tubular spine at the anterior edge
of an overlapping growth lamella in Spinatrypa. Opposing edges grow round towards
one another (see arrows) to meet on the underside.
transverse sections through the ventral muscle scars, a succession of secondary and
tertiary layers in alternation is unconformably overstepped by a thick tertiary pris-
matic myotest (Text-fig. 12). The junction between myotest and underlying shell
layers is sharp (PI. 9, fig. i) and, judging from the way in which successive secondary
and tertiary layers are overlapped, it is evident that earlier-formed parts of the shell
succession which lay in the path of the advancing muscle base were resorbed. An
examination of ultrasonically cleaned ventral adductor and diductor muscle scar
surfaces reveals a fabric very similar to that found in Gryphus. The outlines of
individual crystals are highly irregular and lateral margins of adjacent ones inter-
digitate (PI. 9, fig. 2). These terminal faces of tertiary layer crystals, upon which
deposition took place, are rough and undulating and although some of this unevenness
may be due to secondary diagenetic effects, it is probably for the most part original.
Outside the muscle scars the terminal faces of tertiary layer crystals are virtually the
same as those inside, and no clear-cut distinction between them at the submicro-
scopic level can be made.
Deposition of the atrypid tertiary layer must have taken place in a manner very
similar to that occurring in living Gryphus. Instead of depositing obliquely dis-
posed fibres ensheathed by protein membranes, the tertiary layer epithelium
reverted to deposition in a plane normal to the inner shell surface. As Copper has
shown (1967 : 129), there are some differences in the size and distribution of the
secondary and tertiary layers within the atrypid group as a whole. Both Atrypa
2i8 SHELL STRUCTURE
and Desquamatia examined by 'Stereoscan' show generous interlayering, but in later
Desquamatia, according to Copper, the interlayering decreases. The disappearance
of numerous interlayers and the thickening of the tertiary layer are also typical of
Spinatrypa, Spinatrypina, Atryparia and Kerpina. In Gruenewaldtia and Mimatrypa
the tertiary layer thickening becomes extreme and adjacent crystals merge to produce
a more massive deposit.
(ii) Dayiacea
The Dayiacea include both smooth and plicate forms which bear spiralia with
laterally or ventrally directed apices. In the earliest known genus Cydospira,
however, the spiral lamellae are coiled more or less in a plane parallel to the median
plane of the valves. Although Cydospira is reported to be ajugate, it closely re-
sembles Dayia in morphology. Both have smooth, unequally biconvex shells with
their pedicle valves more convex, and Schuchert and Cooper (1932 : 27) drew atten-
tion to the close similarity in their ventral muscle scars. The only other representa-
tive of the Dayiacea examined was Coelospira, which differs from the other two mainly
in being plicate.
Although much of the shell material of Cydospira sp. from the Upper Ordovician
(Ashgillian) of Pomeroy, Co. Tyrone, Northern Ireland, was altered by recrystalliza-
tion, it was possible to recognize parts of the secondary and tertiary succession. No
primary layer was preserved. Secondary layer fibres which are diamond-shaped in
transverse section measure about 12 /mi in width (PI. 9, fig. 3). The best preserved
parts of the tertiary shell succession were located below parts of the ventral muscle
scars. In those areas, the boundaries between tertiary layer crystals are impersistent
but a prominent depositional banding delineates former cell boundaries (PI. 9, fig. 4).
The thickness of individual growth increments varied between 0-2 /urn and 0-8 /mi
and prominent bands could be traced running across several adjacent crystal bound-
aries. The banding is closely comparable with that observed in sections of the ter-
tiary layer of Gryphus.
A specimen of Dayia navicula (Sowerby) from the Dayia Shales (Ludlovian) of
Shropshire provided the history of exoskeletal secretion in that genus. Both valves
had been largely stripped of their thin outer primary layer but secondary layer fibres
up to 20 /mi wide showed good diamond-shaped outlines in transverse section (PI. 9,
fig. 5). As far as is known, tertiary layer deposits (PI. 9, fig. 6) are restricted to the
posterior regions of the pedicle valve, for no such deposit has been found in the
brachial valve. The median septum which adds thickness to the brachial valve is
composed solely of secondary shell material. Vertically stacked tertiary layer
crystals have clearly defined outlines which measure, on average, 18 /mi in thickness.
These outlines are initially in continuity with the outlines of underlying secondary
layer fibres. The overall pattern of tertiary layer deposition resembles that of
Catazyga in that individual crystals are laterally deflected either one way or the other
at fairly regular intervals to produce a 'jigsaw-puzzle' type of shell fabric. No
interlayering of secondary and tertiary layer deposits was noted.
Although the only specimen of Coelospira available for study (Coelospira saffordi
(Foerste) from the Brownsport Formation of Western Tennessee) was found to be
SPIRIFERIDE BRACHIOPODA
219
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220 SHELL STRUCTURE
partially silicified, remnants of three calcareous shell layers were recognized. The
primary layer, which attains a thickness of about 12 /mi, is composed of narrow
crystallites stacked normal to the outer shell surface. The outlines of secondary
layer fibres tend to be more rounded than those of other Dayiacea or Atrypacea,
apart from Idiospira, and cross-sections reveal orthodoxly stacked groups with gently
curved keels and saddles (PI. 10, fig. i). Shell deposition in the postero-median
region of the pedicle valve was about three times as great as that in the correspond-
ing part of the brachial valve. A thick tertiary layer, which has no counter-
part in the brachial valve, augments the pedicle valve succession (PI. 10, fig. 2). As
in Catazyga, secondary layer fibres comprising the flanks of the pedicle valve pass
laterally into a more massive tertiary layer which coincides roughly with the areas
of ventral muscle attachment. The fabric of the tertiary layer in Coelospira is
similar to that found in Dayia.
(b) Retziidina
The suborder Retziidina comprises costate and multiplicate rhynchonelliform
Spiriferida with a medially directed V-shaped jugum and laterally directed spiralia.
On the basis of presence or absence of shell punctation, the suborder is split into two
superfamilies, respectively the Retziacea and Athyrisinacea (Boucot et al. 1964 : 813).
Specimens of only four punctate genera were available for study. These were
Homeospira evax (Hall) from the Waldron Formation (Upper Silurian) of Indiana,
Rhynchospirina maxwelli Amsden from beds of the Haragan Formation (Lower
Devonian) at White Mound, Murray County, Oklahoma, Hustedia radialis (Phillips)
from the Arden Limestone (Lower Carboniferous), Arden, Lanarkshire, and Retzia
sp. from the St Cassian Beds (Triassic) of Northern Italy.
A well-developed primary layer, on average 25 /mi thick, is characteristic of all
four genera. In the Rhynchospirina (PI. 10, fig. 3) and Homeospira (PI. 10, fig. 4) it
was found to be partially recrystallized, but in Hustedia (PI. 10, fig. 5) and especially
Retzia (PI. 10, fig. 6) features such as the porous texture and fine lineations disposed
normal to the shell layers were seen, reminiscent of the primary layer fabric of Recent
articulates. In Retzia sp. a fine depositional banding with an average periodicity of
0-8 /mi has been recognized (PL n, fig. i). This banding, which is considered to be
diurnal, dips posteriorly at a low angle from the outer shell surface to the inner
primary /secondary shell layer interface.
Fibres comprising the secondary layer of the Retziidina are consistently small.
Indeed, in none of the genera examined were any found which had grown to a width
much in excess of 10 /mi. Secondary layer fibres of Homeospira and Rhynchospirina
are generally rather irregular in outline although this unevenness is probably of
secondary diagenetic origin. However, in Retzia and Hustedia transverse sections
reveal orthodoxly stacked fibres which possess smoothly rounded keels and saddles.
The shape and stacking of the fibres indicate a regular internal secondary shell mosaic
pattern made up of alternating rows of smooth, spatulate terminal faces like those in
Spiriferina. Depositional banding with a periodicity of between 0-15 /mi and 0-4 /mi
was recognized in sectioned fibres of Retzia sp. (PI. u, fig. 2).
SPIRIFERIDE BRACHIOPODA 221
The endopunctate condition of the Retziidina closely resembles that of Recent
Terebratulida. In Homeospira and Rhynchospirina puncta measure about 10 /im
in diameter, whereas in Hustedia and Retzia (Triassic) they measure up to 25 /mi.
Normally the puncta are unbranched, but with continuing deposition below the crests
of ribs, several discrete puncta may gradually encroach upon one another to unite,
eventually, as one central canal (PL 10, fig. 6). As well as being deflected laterally,
secondary layer fibres forming puncta also arch outwards towards the shell exterior.
Within the primary layer, the slightly bulbous distal ends of puncta are separated
from the shell exterior by a thin canopy of calcite between 2 /mi and 4 /mi thick
(PI. n, figs. 3, 4). Although such canopies are grossly recrystallized or broken, it
seems reasonable to assume that they were perforated by minute canals such as are
found in Recent Terebratulida (Owen and Williams 1969) and Spiriferina (Mac-
Kinnon i97ia).
(c) Athyrididina
The Athyrididina are divided into two superfamilies, the Athyridacea and Koninc-
kinacea, to include smooth or plicate, short hinged forms with spiralia directed
laterally and ventrally respectively. The two superfamilies are easily distinguish-
able, since Athyridacea are generally biconvex in profile whereas the Koninckinacea
include only concavo-convex forms.
(i) Athyridacea
The shell structure of early Athyridacea is closely comparable to that of con-
temporary Atrypacea in that three calcareous shell layers are recognizable. In
Meristella atoka Girty, from the Haragan Formation at White Mound, Oklahoma, a
well-developed primary layer measuring up to 20 /mi in thickness can be identified
(PL n, fig. 5) and traces of fine transverse banding, which are indicative of periodic
deposition, are occasionally preserved. Transverse sections through the shell layers
reveal a succession of secondary layer fibres which measure up to 25 /mi in width.
Judging from the regular stacking of secondary layer fibres which display smoothly
curved keels and saddles, it is evident that the internal mosaic comprises alternating
rows of terminal faces with arcuate anterior margins. The tertiary layer is excep-
tionally thick, especially in the pedicle valve (PL n, fig. 6). In sections through the
pedicle valve of Meristina tumida (Dalman) from the Silurian (Wenlock) of Gotland,
tertiary layer crystals stacked normal to the shell surface were found to constitute
over 80 per cent of the calcareous shell succession. Traced inwards from the secon-
dary/tertiary layer interface, vertical intercrystalline boundaries are fairly persistent
but some appear to die out as a result of amalgamation of adjacent crystals (PL 12,
fig. i).
The ventral muscle scars of Meristella and Meristina are deeply impressed in the
postero-median region of the pedicle valve. Transverse sections across the muscle
scars reveal that, apart from causing a localized depression on the inner shell surface,
the tertiary layer fabric is unaffected. It is evident, however, that shell deposition
within muscle scars did not proceed at the same rate as in laterally adjacent
222 SHELL STRUCTURE
areas. The fact that the shell succession is thinner under muscle scars may be
attributable to a partial reversal in the secretory behaviour of the outer epithelium
from mineral to organic exudation as a means of maintaining adhesion between shell
and tissue. In the brachial valve of Meristella the dorsal adductor scars are im-
pressed on secondary shell material The myotest fabric produced by the breakdown
in secondary shell deposition is very irregular (PI. 12, fig. 2) and can be traced running
posteriorly within the shell succession, and diminishing in extent, towards the umbo.
Many Athyridacea are characterized by the development of a cardinal plate ex-
tending across the apical region of the brachial valve. Such a structure, which may
be perforated posteriorly, is built up laterally of outer hinge plates and medially of
either conjunct inner hinge plates or one single plate. In Meristella atoka Girty the
cardinal plate is depressed medially and is supported by a median septum which
extends forward for half to two- thirds the length of the valve. When sectioned
transversely, the structure is Y-shaped, with the base of the letter Y corresponding
to the base of the median septum and the crural bases situated at points represented
by the other two extremities (PL 12, fig. 3). Both the cardinal plate and supporting
septum must have grown as one unit in the same way as that described for the
spondylium simplex oiSkenidioides by Williams and Rowell (1965 : Hii4), for the con-
vex faces of secondary layer fibres (keels) are invariably directed away from the
median plane of the septum. Growth on the underside of the cardinal plate was
continuous with that on the flanks of the median septum and on the upper surface
of the cardinal plate which faces toward the pedicle valve. However, as might be
expected, part of the shell fabric on the upper side of the cardinal plate, which would
be deposited by outer epithelial cells in contact with the dorsal region of the pedicle
base, is grossly modified. In a deposit up to 50 /am thick, which coats the upper sur-
face of most of the cardinal plate, the outlines of individual fibres are destroyed and
replaced by a highly porous fabric (PL 12, fig. 4) which is roughly lineated normal to
the shell surface in a manner reminiscent of a primary layer fabric. Apart from the
sporadic lineations, it may also be compared with the fabric of the neighbouring
dorsal adductor myotesL Presumably the cardinal plate served as the area of
attachment for the dorsal ends of the dorsal pedicle adjuster muscles. Indeed,
within the brachial valve of Waltonia inconspicua (Sowerby), the inner hinge plates
unite medially with a septum in a manner identical to that described for Meristella ;
and on the upper surface of its cardinal plate the secondary mosaic is considerably
modified though not as much as in Meristella.
In most younger Athyridacea, such as Athyris and Composita, deposition of a
tertiary layer did not occur, and the structure of their primary and secondary layers
is unexceptional. The primary layer of Athyris spiriferoides (Eaton) from the
Upper Hamilton Group (Middle Devonian) of New York measures up to 30 /nm in
thickness and is composed of vertically stacked crystallites (PL 12, fig. 5). It is
succeeded by a thick secondary layer composed of orthodoxly stacked fibres with
smoothly convex keels and saddles (PL 12, fig. 6). Mature fibres measure up to
25 /urn in width. The fabric of the primary layer of Composita ambigua (Sowerby)
from the Calmy Limestone (Lower Carboniferous) of Carluke, Lanarkshire, is the
same as that of Athyris spiriferoides, and measures up to 20 /u,m in thickness (PL 13,
SPIRIFERIDE BRACHIOPODA 223
fig. i). Fibres of the secondary layer are indistinguishable in size and disposition
from those of Athyris.
Cleiothyridina deroissii (Leveille) from the Blackbyre Limestone (Lower Carboni-
ferous) at Brockley, Lesmahagow, Lanarkshire, excited more interest. It was
found to possess a primary layer of up to 25 //,m thickness which was succeeded
by orthodoxly stacked secondary layer fibres and, like the profiles of secondary
layer fibres composing the shells of other Athyridacea, those of Cleiothyridina possess
smoothly convex keels and saddles (PL 13, fig. 2). However, over much of the
interior of both valves, secondary layer fibres are succeeded by a thick tertiary layer
deposit composed of tall crystals whose basal parts are continuous with the outlines
of secondary fibres, as in Gryphus vitreus (Born). Of particular interest is the
discovery, in sections through the tertiary layer, of a prominent transverse deposi-
tional banding which is traceable across adjacent crystal boundaries (PL 13, fig. 3).
In general the prominence and periodicity of the banding varies greatly. A fairly
regular banding with an average periodicity of 900 nm was recognized and taken to
reflect diurnal deposition, but even this banding could be subdivided in places into
units no more than 200 nm thick.
It is evident from a study of the distribution of the shell layers in Cleiothyridina
that deposition of all three calcareous shell layers took place simultaneously. How-
ever, adjacent parts of the mantle must have been subject to temporary reversals in
secretory behaviour, for secondary and tertiary layers interdigitate (PL 13, fig. 4), as
do primary and secondary layers closer to the contemporaneous valve margins. The
fluctuations in primary and secondary shell deposition are more intense than those
affecting the tertiary layer and may give rise to a series of frill-like overlapping lamellae
which characterize a number of late Palaeozoic Athyridacea. In Cleiothyridina the
extremities of lamellae are fashioned into long, flat, spinose projections which gener-
ally break off when the fossils are extracted from the surrounding rock matrix. Fine
spines may also develop upon the frilly edges of overlapping lamellae in Athyris.
In certain of the youngest athyridaceans, such as Diplospirella, bifurcations of the
jugal stem gave rise to a pair of accessory spiral lamellae which grew in such a way as
to become intercoiled with the arms of the primary spiralia. Specimens of Diplo-
spirella wissmani (Miinster) and Anisactinella quadriplecta (Miinster) from the St
Cassian Beds (Triassic) of Northern Italy were examined with a view to determining
the skeletal ultrastructure of this stock. In most cases, specimens were small
enough for complete valves to be comfortably accommodated on 1-3 cm diameter
'Stereoscan' stubs. In this way, it was possible to view whole shell interiors and
thereby interpret the growth of particular areas of interest in relation to the overall
fabric.
In sections of Diplospirella wissmani (Munster) the primary layer was found to be
well preserved (PL 13, fig. 5). It is normally about 25 //,m thick and exhibits a fine
lineation disposed roughly normal to the outer shell surface. In the development of
this lineation and its generally porous texture, the primary layer of Diplospirella is
comparable with that found in living articulates. Transverse growth bands are
only sporadically developed. The most striking aspect of the shell structure of
Diplospirella is the size of secondary layer fibres (PL 13, fig. 6 ; PL 14, figs, i, 2).
224 SHELL STRUCTURE
Compared with the fibres of Athyris or Composita, for example, the fibres of Diplo-
spirella are exceptionally large and spatulate terminal faces up to 60 /zm in width
can be discerned even when the valve interiors are viewed under a conventional
light microscope. Evidently the outer epithelial cells responsible for secreting the
secondary layer of Diplospirella were much less mobile than those of most other
articulates, for fibres newly proliferated at the valve margins appear to grow radially
outwards but those located some distance from the commissure are only slightly
reorientated with long axes disposed in such a way as to indicate growth in an anterior
direction only. No exceptional twists, spirals or S-shaped convolutions have been
observed. The only appreciable modification in the secondary shell mosaic occurs
within muscle scars.
Around the anterior margins of scars, the standard secondary shell mosaic breaks
down and is replaced posteriorly by a succession of very long exposed trails of fibres
bearing no recognizable terminal faces (PL 14, fig. 3). Outlines of rather ragged,
asymmetrical trails may extend along the scar for more than half its length. This
breakdown in the normal process of shell deposition is also recognizable in sections
through muscle scars where orthodoxly stacked secondary layer fibres are succeeded
inwardly by a succession of fibres with very irregular, though closely interlocking
outlines (PL 14, fig. 4). In most respects this breakdown in secondary shell deposi-
tion within the muscle scars of Diplospirella is similar to that which has been ob-
served in young Notosaria, except that no arcuate zones of fibres with large terminal
faces occur. At the posterior margins of each muscle scar, the long, exposed trails
are overlapped by a cluster of very small fibres with terminal faces averaging less
than 10 ju,m in width (PL 15, fig. i). Within a relatively short distance however,
the terminal faces of fibres attain dimensions more typical of the secondary layer
mosaic pattern which occurs elsewhere on the shell surface. The occurrence of a
zone of small fibres around the posterior margins of a muscle scar is important since
it provides an indication of the size of outer epithelial cells which must have been
located in that part of the shell. Since terminal faces less than 10 /u,m in width overlap
trails which may exceed 60 p,m in width, it is evident that a substantial size differential
existed between cells located anterior and posterior to the muscle scars. Judging
from the way in which the surface level drops around the anterior margins of muscle
scars, it would appear that parts of the secondary mosaic which lay in the path of
the encroaching muscle base were, to some extent, resorbed. The long exposed
trails within muscle scars are interpreted as being remnants of fibres which were
involved in resorption when formerly located around the anterior periphery of the
scar. Within the muscle scar it is probable that organic membranes completely
ensheathed exposed fibre trails, so that the main function of outer epithelial cells
underlying muscle bases is likely to have been adhesion and not secretion. Since it
is known from a study of living material that the optimum size range for outer
epithelial cells underlying muscle bases is substantially less than that outside, it is
not surprising to find that the first-formed fibres around the posterior margins of
scars are of small dimensions.
The shell structure of Anisactinella quadriplecta (Miinster) is essentially the same
as that recorded for Diplospirella. In the only specimen of Anisactinella available
SPIRIFERIDE BRACHIOPODA 225
for study, a thin primary layer consisting of vertically stacked crystals about 8 /mi
high is preserved (PL 15, fig. 2). The secondary layer fibres are large and attain
widths of more than 60 /mi. Unlike Diplospirella the exterior of Anisactinella is
coarsely plicate, but on the inner shell surface the deposition of secondary layer
material within the radially disposed hollows tends to fill out these external irregu-
larities with the formation of a relatively smooth surface.
(ii) Koninckinacea
The Koninckinacea as presently constituted comprise six genera of small to
medium-sized articulate brachiopods with smooth concavo-convex shells which
enclose a double pair of ventrally directed spires. Despite the distinctive external
shell morphology and an unusual brachidium, the superfamily has received little
attention since the end of the nineteenth century. With the exception of Cadomella,
the genera are perhaps best known as representatives of the Triassic St Cassian fauna
of the Italian Dolomites so extensively collected and figured by Bittner (1890 : 304-
309). It was not until Cowen and Rudwick (1966 : 403-406) discovered a spiral
brachidium in Cadomella davidsoni (Eudes-Deslongchamps) that this Lower Jurassic
genus was recognized as a member of the Koninckinacea.
In the Treatise (1965 : H666) Boucot et al. assign the Koninckinacea and Athyri-
dacea to the suborder Athyrididina and the spiriferide affinities of the koninckina-
ceans were not questioned until Cowen and Rudwick proposed a rearrangement of
this existing classification, based on general shell morphology, with the transference
of the superfamily, amended to include Cadomella, from the Spiriferida to the Stro-
phomenida. However, the strongly concavo-convex shell profile and the morphology
of the apical region, though reminiscent of many Strophomenida, are not diagnostic
features. In addition, the statement made by Cowen and Rudwick (1966 : 404) that
the pedicle foramina of Koninckella liassina Bouchard, K. triassina Bittner and
Amphidina suessi Laube 'are definitely supra-apical' is not supported by recent
observations on K. triassina Bittner, Amphidina amoena Bittner, Cadomella david-
soni (Eudes-Deslongchamps) and C. moorei (Davidson) made by Brunton and
MacKinnon (1972 : 410). As will be shown presently, the nature of the calcareous
shell succession in Koninckinacea is comparable with that of a number of Spiri-
ferida, but quite unlike that of any Chonetidina (Williams i_968a : 46) ; therefore,
in the absence of any morphological detail, macroscopic or microscopic, that would
serve to establish strophomenide identity, there now appears to be no valid reason
for removing the Koninckinacea from the Spiriferida.
This account of the shell ultrastructure of the Koninckinacea is based on an ex-
amination of specimens belonging to three genera : Koninckina leonhardi (Wissman)
and Amphidina amoena Bittner from the St Cassian Beds (Triassic) of Northern
Italy, and Cadomella davidsoni (Eudes-Deslongchamps) and C. moorei (Davidson)
from Liassic clays near Caen, France.
The primary layer of Koninckina is about 10 to 12 /mi thick. In transverse
section it is usually discernible as a series of closely packed crystallites between
0-5 /mi and 2-0 /mi in width which are stacked normal to the isotopic boundary
between the primary and secondary shell layers (PI. 15, fig. 3). On the outer shell
226 SHELL STRUCTURE
surface, faint concentric growth lines cut across a fine radial lineation (PI. 15, fig. 4)
which appears at higher magnifications to be a series of narrow troughs and ridges.
The ridges are comparable in width and stacking to that of the crystallites observed
in thin section, and because of their consistency and regular spacing are considered
to be an original feature of the outer shell surface. Presumably the inner bounding
membrane of the periostracum, which must have provided an outer organic cover to
both valves, was moulded by crystal growth into a series of radial grooves and fine
ridges corresponding in negative to the undulations on the shell surface. Possibly
organic strands or membranes extended through the primary layer by way of the
spaces between crystallites to join up with the organic components of the secondary
shell layer. Apart from being slightly thicker, the primary layer of Amphiclina is
little different from that of Koninckina.
Williams (ig68a : 34) noted that the secondary layer of Koninckina is composed
of fibres which grow to an unusually large size in comparison with the secondary
layer fibres of most other articulates. On the internal surfaces of both valves the
terminal faces of secondary layer fibres are rhomb-shaped (PI. 15, fig. 5) and not
spatulate as is common in Recent Terebratulida, Rhynchonellida and some Spiri-
ferida. This distinctive secondary shell mosaic pattern has the general appearance
of diagonally intersecting rows of rhomb-shaped faces but such rows are not perfectly
FIG. 13. Plan of the secondary shell mosaic on the internal surface of a valve of Koninckina,
showing the diamond-shaped outlines of terminal faces. The more normal, smoothly
curved mosaic, such as is found in Recent Rhynchonellida and Terebratulida, is shown
by broken lines for comparison.
SPIRIFERIDE BRACHIOPODA
227
FIG. 14. a. Stylized transverse section of the secondary shell of a Recent rhynchonellide or
terebratulide showing the characteristic shape and stacking of fibres, b. Stylized
transverse section of the secondary shell of Koninckina showing the characteristic
diamond-shaped outlines of fibres.
linear, as the outline of each terminal face is displaced fractionally from its neigh-
bours. To derive this internal surface pattern from the more typical spatulate
mosaic requires only a sharpening of the arcuate junction between the calcite and
protein secretory zones in the overlying outer epithelium (Text-fig. 13). Diamond-
shaped terminal faces with diagonal lengths and widths measuring up to 45 /mi and
30 /tin respectively have been observed in both Koninckina and Amphiclina (PI. 15,
fig. 6).
The shape and stacking of secondary layer fibres in transverse section are dependent
initially on the slope and spatial relationships of the corresponding outer epithelial
cells on the inner shell surface. For example, in a Recent rhynchonellide or tere-
bratulide, cross sections of a typical fibre show that it is bounded by an inwardly
curved surface (the keel) which is truncated by an outer one made up of two curved
lateral areas and one median depression (the saddle) (Text-fig. I4a). The profile of
the inner and outer surfaces of a fibre correspond to the foreshortened outlines of the
anterior and posterior boundaries of the terminal face. Since both the anterior as
well as the posterior boundaries on the terminal face of the koninckinacean secondary
layer fibre are angular, the cross-sectional outline of the fibre is correspondingly
modified. Transverse sections of Koninckina and Amphiclina reveal that the fibres
are roughly diamond-shaped with inner and outer surfaces variably truncated
(Text-fig. J-4b).
In some, if not all, specimens of Koninckina recovered from the St Cassian beds,
the secondary shell fabric is almost certainly original because fibres in longitudinal
and transverse sections exhibit a fine depositional banding (PI. 16, figs. 1,2) of variable
periodicity, which probably represents slight fluctuations in the physiological
behaviour of the corresponding outer epithelial cells. The mean periodicity of 37
bands measured from cross-sections of six adjacent fibres was 0-89 /nm (range 0-58
228 SHELL STRUCTURE
to 1-54 /um). However, until more is known of the factors controlling mineral
secretion in living brachiopods, such as the effects of temperature, light and salinity
of the local environment, feeding habits, availability of food, tidal conditions, etc.,
the precise significance of such depositional features must remain in some doubt.
Some distance in from the shell edge of Koninckina and Amphiclina, the secondary
layer fibres are succeeded by a tertiary layer deposit which thickens towards the
centre of both valves. The change-over from secondary to tertiary deposition cor-
responds with the anterior extremities of the primary lamellae which comprise the
first and broadest convolution of the spiral brachidium. Posterior to this line, the
narrow shell cavity is moulded to the shape of the two shallow, ventrally directed
coils, thus producing a dome-shaped swelling (PI. 16, fig. 3) on either side of the
brachial valve mid-line and a pair of depressions in the pedicle valve. Super-
imposed on each outgrowth (or depression) is a spiral groove along which are chan-
nelled the arms of the spiralia. In addition, the shell surface is pock-marked by' a
number of shallow pits which appear in some parts to be distributed along the spiral
grooves. However, it seems unlikely that the pits are related to any part of the
brachial structure, and an interpretation favouring some form of gonadal markings
(such as are commonly found in Atrypa) seems more plausible. Impressions related
to brachidia (and gonads) have been observed in both Koninckina and Amphiclina.
An examination of the tertiary layer in Koninckina, in plan as well as in section,
reveals a shell fabric closely comparable with that observed in living Gryphus. The
secondary shell mosaic, with its distinctive diamond-shaped terminal faces, breaks
down into a grossly modified surface pattern which appears as an irregularly anasto-
mosing network of intercrystalline boundaries (PI. 16, fig. 4). The rough undulating
topography of each growing face contrasts with the smoothness of the secondary
layer terminal faces. Dimensions of faces are difficult to measure, because of their
irregularity in outline, and a better estimate of their dimensions can be made from
sections cut at right angles to the plane of growth. Seen in depth, the tertiary layer
is composed of vertically stacked and tightly interlocking columns of calcite,
separated from one another by clear-cut boundaries (PI. 16, fig. 5). Although the
isotopic boundary between the secondary and tertiary layers is well defined, it is
evident that the vertically stacked columns grew in continuity with the underlying
secondary fibres. There is a one-to-one correspondence between tertiary layer
columns and secondary layer fibres for, in longitudinal sections showing the secon-
dary/tertiary layer junction, each rod-like fibre of the secondary layer gives rise to a
single vertical column (PI. 16, fig. 6).
The mode of formation of the tertiary layer in Koninckina must have been very
similar to that occurring in living Gryphus. At a certain distance from the shell
edge, the outer epithelial cells ceased to migrate in the horizontal plane but continued
to secrete calcite, so that a thick deposit was laid down normal to the shell surface.
Over certain parts of the inner shell surface of Koninckina, notably the postero-
median region behind muscle scars, there is a regrowth of the secondary layer fibres
on top of the tertiary layer. Generally one tertiary layer column will be succeeded
by one fibre but sometimes two or rarely three branches emerge at this inner isotopic
boundary.
SPIRIFERIDE BRACHIOPODA 229
(d) Spiriferidina
The Spiriferidina constitute the largest and most diverse suborder of all spire-
bearing brachiopods. In general the spiriferidine shell is broadly strophic and
possesses a well-developed ventral interarea. The spiralia are directed laterally or
postero-laterally.
The problems of spiriferid classification are well summed up by George (1933 : 423-
456) who recognized the lack of reliable morphological criteria on which a workable
and satisfactory scheme could be founded. In the Treatise classification, Pitrat
(1965 : H667) considered the existence of longitudinal striations on the cardinal
process to be a feature of critical importance. Using this fact as his main basis for
suprageneric classification, he separated the 'non-striate' Cyrtiacea (impunctate) and
Suessiacea (punctate) from the 'striate' Spiriferacea (generally impunctate, plicate),
Reticularacea (impunctate, smooth) and Spiriferinacea (punctate).
(i) Cyrtiacea
The Cyrtiacea as defined in the Treatise (1965 : £[667) include the Eospiriferinae
and their impunctate derivatives, the Cyrtiinae and the Ambocoeliidae. Specimens
of Eospirifer, the earliest cyrtiacean, were unavailable for study but sections of the
related genus Cyrtia exporrecta (Wahlenberg) from the Silurian of Coalbrookdale,
Shropshire, reveal a thin, recrystallized primary layer measuring up to 10 jum in
thickness. Fibres of the secondary layer are unlike those of contemporary Atrypi-
dina in that they exhibit symmetrical profiles with rounded keels and saddles instead
of being diamond-shaped (PL 17, fig. i). From the regular stacking of fibres and
their smooth outlines, it can be deduced that the internal mosaic consists of alternat-
ing rows of broadly spatulate terminal faces. On average, fibres measure about
12 /u.m in width.
The Eospiriferinae and the Cyrtiinae are thought to be very closely related, since
the two groups are substantially the same except for overall shell shape and modifica-
tions of the delthyrium (Pitrat 1965 : H667). The smooth-shelled, generally plano-
convex Ambocoeliidae are less emphatically related to the other two subfamilies,
but are grouped with them mainly on account of their possession of a non-striate
cardinal process.
Ambocoelia umbonata (Conrad) from the Hamilton Group (Middle Devonian) of
New York possesses a well-developed primary layer up to 40 /*in thick which is best
preserved around the commissures of mature specimens. In this area, primary and
secondary shell layers interdigitate as the two major components of overlapping
growth lamellae (PI. 17, fig. 2). The curved outlines of secondary layer fibres in
section indicate an orthodox secondary shell mosaic pattern with terminal faces
about 20 /Ltm wide (PI. 17, fig. 3). In the vicinity of muscle scars the regular stacking
of fibres breaks down and outlines of adjacent fibres become ragged andimpersistently
welded together. The interior of a brachial valve of the related genus, Crurithyris
sp. from the Finis Shale (Pennsylvanian) of Texas, was sufficiently free from en-
closing rock matrix to allow examination of the surface mosaic. As might be
expected, the surface was badly etched and pitted but the outlines of individual
230 SHELL STRUCTURE
secondary layer terminal faces, on average 20 pm wide, were still recognizable
(PI. 17, fig. 4). In the umbonal region of the brachial valve a narrow cardinal pro-
cess lies between two prominent, inwardly convex inner socket ridges (PL 17, fig. 5).
The base of the cardinal process is cylindroid and rises posteriorly to become densely
tuberculate (PI. 17, fig. 6), but no longitudinal striation, such as was found in
Spiriferina, could be detected.
(ii) Suessiacea
Apart from the monotypic genus Suessia which constitutes the family Suessidae,
the Suessiacea includes representatives of the family Cyrtinidae. Most genera are
punctate and characterized by a weakly convex brachial valve and hemipyramidal
pedicle valve. Although resembling most Cyrtiacea in the possession of a non-
striate cardinal process as well as in external morphology they differ mainly in the
development of a ventral median septum and dental plates which may merge to
form a spondylium-like structure.
Two species of Cyrtina were examined in order to help determine the skeletal
fabric of the superfamily. Specimens of Cyrtina alpenensis Hall and Clarke, from the
Middle Devonian of Rockport, Alpena County, Michigan, possess well-developed
primary and secondary shell layers. The primary layer, on average about 20 ju,m
thick, has a spongy appearance and is traversed by a faint lineation disposed normal
to the shell exterior (PI. 18, fig. i). Fibres of the secondary layer are small, present-
ing a mean width of 10 /urn. In both valves the secondary layer fibres are outwardly
deflected around puncta which may measure up to 25 /mi in diameter. The puncta
appear to penetrate the primary layer, but due to the homogeneity of the sedimentary
infilling of puncta with the fabric of the primary layer, it was impossible to dis-
tinguish any distal coverings. Branching puncta may occur sporadically in both
valves.
On the interior of the pedicle valve, the dental plates are strongly developed and
converge rapidly to unite with a high, blade-like median septum. The septum of
Cyrtina is unusual in that it supports a narrow medially partitioned chamber along
its posterior facing edge. This chamber, the tichorhinum, extends from the umbo
to the dorsal edge of the median septum and is subtended laterally by the inner
surface of the dental plates. In some species of Cyrtina the tichorhinum is reported
to be incompletely partitioned (Amsden 1958 : 135). In transverse sections of
Cyrtina sp. from the Upper Devonian of Rockford, Iowa, the tichorhinum is seen to
originate as a bulbous triple-branched extension of the median septum comprising
one median partition and two lateral, curved walls (PI. 18, fig. 2). Judging from the
disposition of secondary layer fibres which tend to run parallel to the long axis of
the tube, it is evident that the tichorhinum was fashioned as a result of the localized
evagination of outer epithelium situated on both sides of the postero-dorsal edge of
the median septum. The reasons for evagination having occurred in the first place
are not clear, but it is evident that the greater part of the median septum served as a
muscle attachment area. Two discrete myotest shell fabrics are recognizable in
transverse sections through the median septum (Text-fig. 15). The first is situated
close to the median plane of the septum and is overlapped by a subsequent deposit of
SPIRIFERIDE BRACHIOPODA
tichorhinum.
231
adductor
myotest
FIG. 15. Stylized transverse section through the ventral median septum and
tichorhinum of Cyrtina, showing the distribution of myotest.
secondary shell material. Above the level of the fused dental plates this myotest
can be traced running into the tichorhinum. The second myotest is situated on
either side of the septum below its junction with the dental plates and extends as far
as the floor of the valve (PL 18, fig. 3). Since the first myotest is unaffected by the
union of the dental plates, it is evident that its former position of growth was located
forwards (and dorsal) of the point where the dental plates join with the septum.
This would correspond to a position on the septum which is situated at its postero-
dorsal extremity close to the hinge line. Since the second myotest is located on the
flanks of the septum below the dental plates, it must comprise part of a muscle scar
which is impressed further back on the septum at a lower level within the hemi-
pyramidal pedicle valve.
Despite its unusual pedicle valve morphology, the musculature of Cyrtina was
probably no different from that of other articulate brachiopods. Certainly the
emplacement of muscles in the brachial valve was quite orthodox. On the floor of
the brachial valve are two pairs of adductor scars with a bilobed cardinal process
situated in the umbonal region (Hall and Clarke, 1894 : 763). The muscle scar
layout in the pedicle valve of Cyrtina can best be understood by making direct
comparison with the pedicle valve musculature in Recent genera (Text-fig. i6a, b).
In Notosaria, for example, two small adductor scars are bordered antero-laterally by
the ventral diductor and adjuster scars. Extending this arrangement to Cyrtina,
it seems most likely that the ventral ends of the adductors were inserted within the
tichorhinum as well as being attached to the postero-dorsal part of the septum, and
232
SHELL STRUCTURE
that the diductors ran obliquely forward from the cardinal process to attach to the
antero-lateral parts of the median septum (Text-fig. i6c). The ventral adjuster
muscles were probably attached to the antero-lateral surface of the dental plates.
The transference of the areas of ventral muscle attachment to a median septum
was accompanied by an adjustment in the structure of the spiral brachidium. The
innermost coils of both calcareous spires of Cyrtina are situated very close to one
another and joined by a sharply pointed, anteriorly directed jugum (Text-fig, lya, b).
The apices of the spiralia are directed obliquely posterior and extend well within the
lateral cavities of the hemipyramidal pedicle valve.
c.
FIG. 16. a, b. Views of the interiors of the pedicle valves of Cyrtina (a) and a more con-
ventional articulate such as Notosaria (b), showing the relative location of muscle
attachment areas, c. Cut-away diagram of Cyrtina showing the inferred restoration of
the adductor and diductor muscle systems.
(iii) Spiriferacea
The Spiriferacea is by far the largest of the five superfamilies comprising the
Spiriferidina. Their shell form is variable but in general it tends to be rather trans-
verse with either angular or slightly rounded cardinal extremities. In most cases
maximum width is attained across the hinge line, but in some forms, such as the
Brachythyrididae, the hinge line is substantially short of maximum width. The
earliest Spiriferacea such as Delthyris and Howellella appeared at much the same
time (Lower Silurian) as the first cyrtiaceans Cyrtia and Eospirifer. In such early
genera, lateral plications are few and the fold and sulcus are generally smooth ;
however, in later Spiriferacea costation became more intense and varied as did the
nature of concentric growth lamellae. In addition, there was considerable variation
in the development of the finer elements of the surface ornament, such as spines,
granules and capillae.
SPIRIFEKIDE BRACHIOPODA
233
a.
b.
FIG. 17.
Dorsal (a) and lateral (b) views of Cyrtina showing the disposition of the
spiral brachidium.
The shell structures of two genera assigned to the Delthyridae were investigated.
These were Delthyris saffordi (Hall) from the Brownsport Formation (Upper Silurian)
of Western Tennessee and Kozlowskiellina velata (Amsden) from the Haragan Forma-
tion (Lower Devonian) at White Mound, Murray County, Oklahoma. No recog-
nizable primary layer was preserved in Delthyris, but the fibres of the secondary
layer, measuring up to 25 jitm in width, displayed smoothly curved outlines of keels
and saddles (PI. 18, fig. 4). The regular stacking of fibres as seen in transverse
section indicates the development of an internal surface mosaic comparable with that
observed in Spiriferina. Some sections through fibres reveal traces of a transverse
banding with an average periodicity of about 0-4 /mi, which is considered to be
depositional. In Kozlowskiellina a primary layer measuring up to 10 /mi in thick-
ness is preserved (PL 18, fig. 5). The shape and stacking of transversely sectioned
secondary layer fibres, which measure on average 20 /urn in width, point to an internal
secondary shell mosaic pattern consisting of alternating rows of terminal faces with
smooth spatulate outlines (PI. 18, fig. 6). In the posterior parts of both valves, in
particular the pedicle valve, the secondary layer attains considerable thickness. In
some instances earlier-formed parts of exoskeletal outgrowths such as the crura and
ventral median septum may be identified by the distinctive stacking of their fibres.
Transverse sections through a crus of Kozlowskiellina reveal that it grew in much the
same way as that described for the same structure in Recent Terebratulida and
Rhynchonellida, with the growth of fibres along its length (PI. 19, figs. I, 2, 3). The
fibres are so arranged as to indicate deposition on the ventro-lateral side of the crus
only, with the dorso-median facing side exposing long trails without terminal faces
(cf. Williams iQ68a : text-fig. 12, p. 17). In both the brachial and pedicle valves of
Kozlowskiellina a myotest shell fabric could be recognized. For example, within
the ventral diductor myotest there is a sudden breakdown in normal secondary shell
deposition with the replacement of orthodoxly stacked fibres by an irregular, semi-
granular accretion of calcite forming a layer about 50 /mi thick (PI. 19, fig. 4). The
first few rows of secondary layer fibres which succeed the myotest deposit are
234 SHELL STRUCTURE
noticeably small, being less than 10 /mi in width. In this respect they are com-
parable with the narrow zone of small fibres which overlap the posterior margins of
muscle scars in Notosaria. Normal secondary shell growth does not become fully
re-established behind the ventral diductor myotest, for transverse sections reveal the
subsequent deposition of a semiprismatic layer of considerable thickness. This
deposit resembles, in places, the 'jigsaw-puzzle' type of shell fabric that characterizes
the tertiary layer of Dayia navicula (Sowerby) .
While not showing the widespread development or regularity of the tertiary layer
of living Gryphus, this localized deposit in Kozlowskiellina is quite distinct from the
secondary layer which incorporates all exoskeletal outgrowths as well as adjacent
parts of the valve floor. The location of the deposit may provide some clue as to its
origin. Outer epithelial cells which secrete secondary layer fibres are known to
migrate laterally across the floors of valves leaving trails of calcite marking the
routes along which they proceed. It is possible that those outer epithelial cells
situated behind the ventral muscle bases of Kozlowskiellina were unable to migrate
forwards or laterally fast enough and thus contributed to the build-up of shell
material which was deposited in a plane roughly normal to the inner shell surface.
This hypothesis, however, can only be used in an attempt to explain the development
of a tertiary shell fabric behind muscle scars in forms such as Kozlowskiellina, and
not the widespread tertiary layer deposit as is found in other Spiriferida like Cleio-
thyridina.
The discovery of this incipient tertiary layer in Kozlowskiellina poses the question
as to whether such a deposit is characteristic of other related genera. Unfortunately
no other specimens were available for comparison under the scanning electron
microscope, although Krans (1965) has examined the shell structure of a number of
Delthyridae by means of cellulose acetate peels. In a study which included Devonian
species of Howellella, Howittia, Hysterolites, Spinella, Paraspirifer, Brachyspirifer and
Euryspirifer, Krans reports the growth and development of only two calcareous shell
layers, the primary and secondary layers. From the primitive delthyrid stock are
descended a large number of Spiriferacea which are subdivided, on the basis of
differences on external and internal morphology, into eight other families.
The shell exterior of Mucrospirifer sp. from the Middle Devonian of Michigan is
covered by a primary layer about 12 /mi thick which is lineated normal to the iso-
topic boundary between the primary and secondary layers (PL 20, fig. i). The first
few rows of secondary layer fibres are small, measuring less than 8 /mi in width, but
when traced further inwards they show an increase in size to a maximum of 15 /mi
width. All fibres are orthodoxly stacked and display evenly curved keels and saddles
(PL 20, fig. 2).
No specimens of Fimbrispirifer were available for study, but Krans (1965, pi. 9,
figs. 3, 6) figures sections of two species from the Devonian of Spain which appear to
possess a standard primary and secondary shell succession.
The shell structure of Spinocyrtia sp. from the Middle Devonian of Michigan is
unexceptional. It possesses a recrystallized primary layer which measures about
12 /mi in thickness (PL 20, fig. 3). Fibres of the secondary layer, although com-
parable in shape and stacking with those of Mucrospirifer, are generally smaller.
SPIRIFERIDE BRACHIOPODA 235
Young fibres which succeed the narrow zone of primary shell deposition located
around the shell edge are generally about 4 /zm wide, but mature fibres which are
laid down well within the shell interior attain, on average, a width of 10 /zm (PI. 20,
fig. 4)-
Only fragments of a pedicle valve of Syringothyris cuspidata (Martin) from the
Lower Carboniferous of Staffordshire were obtainable for the purpose of sectioning.
Parts of fibrous secondary layer were recognizable (PI. 20, fig. 5) but no primary
layer was present. Syringothyris differs from all other Spiriferacea in being pene-
trated by puncta measuring up to 20 pm in diameter around which the secondary
layer fibres are outwardly deflected (PL 20, fig. 6). Sass (1967 : 1244) has inves-
tigated the shell structure of six species of Syringothyris and found all of them to be
punctate. In addition, he reports that the shell of Syringothyris comprises three
calcareous layers, namely the primary, secondary and prismatic (tertiary) layers.
Within the tertiary layer the puncta are traceable as irregular passageways which
run along the boundaries of adjacent crystal faces (Sass 1967 : 1244). Certain
generally impunctate spire-bearing brachiopods (Licharewiinae), which are found in
beds of Upper Carboniferous and Permian age, are also assigned to the family
Syringothyridae by Pitrat (1965 : H692). In most cases they appear to be mor-
phologically indistinguishable from the Spinocyrtiidae but as the last surviving
representatives of this family are considered to have become extinct during the late
Devonian, direct descent of the Licharewiinae from such a stock is considered un-
likely. Armstrong (ig68a. : 183) found only two calcareous shell layers in the punc-
tate genus Subansiria from the Permian of Australia.
Investigations of the shell structure of the Devonian Costispiriferidae were con-
fined to the finely ribbed form, Theodossia hungerfordi (Hall) from the Hackberry
Stage (Upper Devonian) of Iowa. The primary layer, which may be up to 25 pm
thick, is succeeded by regularly stacked secondary layer fibres which attain a width
of about 10 /zm. Exoskeletal outgrowths such as teeth and spiralia (PL 21, fig. i)
are built up from secondary layer fibres. In the postero-median parts of the shell a
tertiary layer is developed. This thick inner layer consists of well-defined narrow
crystals on average about 10 ^m in width which are stacked normal to the inner shell
surface (PL 21, fig. 2).
The shell structure of two representatives of the Costispiriferidae were investigated.
These were Tenticospirifer cyrtiniformis (Hall and Whitfield) from the Hackberry
Stage (Upper Devonian) of Iowa, and Syringospira prima Kindle from the Percha
Formation (Upper Devonian) of New Mexico. In both valves of Tenticospirifer the
calcareous shell succession was found to be in a particularly good state of preserva-
tion. The primary layer which may measure up to 45 /xm in thickness has a porous
texture and bears traces of a faint lineation disposed normal to the shell exterior
(PL 21, fig. 3). Fibres of the secondary layer measure, on average, 10 jum in width
but although outlines of fibres appear in transverse section to be flattened in the style
of Hemithiris (Williams I97ib : pi. i, fig. 3b), they are nonetheless orthodoxly
stacked (PL 21, fig. 4). This levelling out of keels and saddles is considered to reflect
a slight change in the profiles of terminal faces from spatulate to sub-rectangular in
outline. Within the vicinity of muscle scars, the standard secondary layer fabric
is
236
SHELL STRUCTURE
uniformly-
crystalline
zone
secondary
layer
primary
layer
b.
a.
. — umbo
FIG. 1 8. a. Longitudinal section through a pedicle valve of Syringospira showing the
development of a series of overlapping partitions, b. Stylized section through a partition
and shell wall of Syringospira showing the intervening uniformly crystalline zone.
is grossly affected and the boundaries between myotest and earlier-formed parts of
the shell succession are abrupt. The ultrastructure of the myotest is difficult to
decipher but judging from its semigranular appearance in transverse section (PI. 21,
fig. 5) it is probably composed of small irregular fibres which are impersistently
welded together in a manner reminiscent of the ventral myotest of Notosaria.
Syringospira, like Tenticospirifer, possesses a well-developed primary layer which
may measure up to 40 /Am in thickness. Sections through the primary layer reveal
a dense vertical striation on which there is superimposed a spongy fabric (PI. 21,
fig. 6). Secondary layer fibres are narrow and seldom exceed 10 /nm in width. Shell
growth in Syringospira was accompanied by the development of a succession of over-
lapping partitions (Text-fig. i8a) within the umbonal cavities of both valves (Cooper
1954 : 328). The ultrastructure and mode of formation of these blister-like plates
have already been described by Williams (iQ7ia : 66). Each blister is composed of
conventional secondary layer fibres. Williams' view that secretion of an organic
seeding shell preceded the deposition of fibres away from the valve floor is supported
by the discovery of a uniformly crystallized zone, up to 35 /mi wide, which lies sand-
wiched between the junction of two adjacent partitions (PI. 22, fig. i ; Text-fig. i8b).
A temporary reversion to wholly organic exudation is by no means unlikely for
similar changes in secretory behaviour are known to occur periodically in living
Rhynchonellida and Terebratulida. Organic layers, believed to be composed of
protein, have been found within the calcareous shell succession of Hemithiris psittacea
(Gmelin). As such deposits tend to be exuded over the entire shell surface the optical
properties of the total shell fabric become affected. Valves of Hemithiris which
SPIRIFERIDE BRACHIOPODA 237
possess organic interlayers are invariably black in colour. In the terebratulide
Magasella sanguined (Leach) exudation of a thin organic layer facilitated the back-
ward slide of the mantle edge during its periodic retractions (Williams igjia. : 64).
A temporary reversal to organic deposition may have served much the same function
in Syringospira as it does, at present, in Magasella. Just as the terebratulide mantle
becomes detached from the adjacent shell surface (caeca included) so also is it likely
that the mantle of Syringospira detached itself in part from the remainder of the valve
floor. The space created by this movement may have become temporarily rilled
with fluid but in any case it is likely that exudation of a temporary organic covering
followed in order to seal off the space and provide a convenient seeding sheet for the
secretion of a more rigid partition composed of secondary layer fibres and their
organic sheaths.
The shell structure of the family Spiriferidae, as represented by Spirifer trigonalis
Martin from the Lower Carboniferous of Lanarkshire and Neospirifer cameratus
(Morton) from the La Salle Limestone (Pennsylvanian) of Ohio, is variable. In
Neospirifer, primary and secondary shell layers are clearly recognizable (PL 22,
fig. 2). The primary layer which measures up to 40 /zm in thickness is similar in
texture to the primary layer of Tenticospirifer. It is rather porous and lineated
normal to the outer shell surface. Fibres comprising the secondary layer are
orthodoxly stacked and measure up to 15 /xm in width. The calcareous shell suc-
cession of S. trigonalis differs from that of most other Spiriferacea in that it incor-
porates a well-developed tertiary layer. Three shell layers were first recognized in
S. trigonalis by Dunlop (1962 : 483) who named them the lamellar (primary) layer,
fibrous (secondary) layer and columnar (tertiary) layer. A 'Stereoscan' examination
of both valves of S. trigonalis confirms most of Dunlop's findings. A primary layer
about 15 /xm thick is succeeded by a secondary layer of fibres, on average 20 /u,m
wide, which are roughly diamond-shaped in profile (PL 22, fig. 3). Vertically stacked
crystals comprising the tertiary layer of 5. trigonalis occupy the greater part of the
interior of both valves (PL 22, fig. 4). Towards the periphery of both valves secon-
dary and tertiary layers may interdigitate (PL 22, fig. 5). Dunlop's view (1962 : 488)
that the interlayering is due to fluctuations in the rate of shell growth is supported
by my own observations. However, there are no sharp depositional breaks at any
junction between secondary and tertiary layers, as Dunlop supposes, but occasionally
slight variations in chemical composition of parts of the tertiary layer may produce,
on etching, prominent growth lines which might be interpreted as such at lower
magnifications. The tertiary layer fabric is grossly affected in the vicinity of muscle
scars. Sections through a ventral muscle scar of one specimen of S. trigonalis reveal
a myotest comprising narrow, irregular fibrous outlines, which in places almost
tends to become finely granular (PL 22, fig. 6).
Representatives of the family Brachythyrididae differ from those of the family
Spiriferidae mainly in being less transverse, with the width of the hinge line generally
falling well short of maximum width. A well-preserved specimen of Choristites
mosquensis Buckman from the Upper Carboniferous of the Moscow region, U.S.S.R.,
was used to determine the skeletal fabric of the family. The shell structure of
Choristites is similar to that of Spirifer trigonalis in that three calcareous shell layers
238 SHELL STRUCTURE
are present. The primary layer, measuring up to 25 /u,m thick, is normally recrystal-
lized but it can still be recognized in sections as a uniform band of narrow, vertically
stacked crystals which blanket the outer surface of both valves (PI. 23, fig. i). The
secondary and tertiary layers, by contrast, are well preserved. In transverse
sections, the secondary layer is seen to be built up of orthodoxly stacked fibres,
averaging 10 /*m in width, which display smoothly curved keels and saddles (PL 23,
fig. 2). In both pedicle and brachial valves, the secondary layer is succeeded by a
well-developed tertiary layer deposit (PL 23, fig. 3). The vertically stacked crystals
of the tertiary layer may vary from 10 /u,m to more than 20 pm in width, due pre-
sumably to occasional localized breakdowns in the deposition of bounding organic
membranes which may allow two or three adjacent crystals to merge as one. Never-
theless, the boundaries between crystals are normally upright, so it can be assumed
that, during deposition of the tertiary layer, little or no lateral migration of outer
epithelial cells took place. The tertiary layer of Choristites is characterized by a
prominent transverse depositional banding with an average periodicity of 2 /mi.
Within each 2 /xm-deep band, several more indistinct transverse bands may occur
(PL 23, fig. 4). Approximately five minor bands may fit within one 2 /nm band,
giving an average periodicity for the minor banding of 0-4 p.m. The latter value is
consistent with measurements of fine depositional bandings recorded within the ter-
tiary layers of other Spiriferida (and also Gryphus) and is thus considered to be
diurnal. It is tempting, therefore, to rationalize the more prominent 2 /x.m bands in
Choristites in terms of some other less frequent, yet still regular influence, such as
fluctuating tidal behaviour. The secondary and tertiary layers of Choristites are seen
to interdigitate frequently, as in S. trigonalis (PL 23, fig. 5). Muscle emplacement
also gave rise to modifications in skeletal fabric similar to those observed in S.
trigonalis. In the vicinity of muscle scars, the standard secondary or tertiary layers
are disrupted and replaced by a deposit about 30 ^m thick consisting of small,
irregularly stacked fibres which may, in places, become more massive due to the
welding together of adjacent margins (PL 23, fig. 6).
For comparison with Choristites, a specimen of Brachythyris sp. from the Lower
Carboniferous of Kildare, Ireland, was sectioned. Although both valves proved to
be badly altered, localized patches of secondary and tertiary layer deposits were
positively recognized and allowed the calcareous shell succession for that genus to be
established (PL 24, figs. I, 2). In most respects, the calcareous shell succession of
Brachythyris appears to be the same as that described for Choristites.
(iv) Spiriferinacea
The shell structures of three Carboniferous representatives of the Spiriferinacea
were investigated with a view to making a general comparison with the standard
shell succession of Spiriferina walcotti. These were Crenispirifer sp. from the La
Salle Limestone (Pennsylvanian) of Ohio, and Punctospirifer scabricosta North and a
specimen labelled as 'Spiriferina cristata var. octoplicata' (tentatively referred to
Spiriferellina cristata (Schlotheim)), both from Ashfell, Westmorland. Of these three,
'S. crista var. octoplicata' was the least well preserved. A section through the
pedicle valve of this specimen exposed a secondary layer built up of irregular fibres
SPIRIFERIDE BRACHIOPODA 239
which measure, on average, 12 /mi in width. The fibres are outwardly deflected to
form cylindroid canals (puncta) which have a mean diameter of 20 /mi (PL 24, fig. 3).
No primary layer was preserved.
The shell of Punctospirifer scabricosta North was somewhat better preserved than
that of the 5. cristata, and a primary layer measuring 25 /mi in thickness was clearly
recognizable (PI. 24, fig. 4). Fibres of the secondary layer are orthodoxly stacked
and exhibit smoothly rounded keels and saddles like 5. walcotti (PI. 24, fig. 5). The
puncta measure up to 30 /mi diameter (PI. 24, fig. 6).
The Crenispirifer sp. proved to be the most useful specimen for comparison with
S. walcotti. Both primary and secondary shell layers are well preserved. The
primary layer, which has a spongy texture, may measure up to 40 /mi in thickness
(PI. 25, fig. i). It is succeeded by an orthodoxly stacked secondary layer, composed
of fibres on average 10 /mi wide. Puncta up to 25 /mi in diameter permeate both
shell layers (PI. 25, fig. 2), but no perforate canopies covering the distal ends of canals,
as were found in S. walcotti, could be detected. The interior of the pedicle valve of
Crenispirifer is divided medially by a high septum which like an identical structure
in 5. walcotti must have functioned as a muscle-attachment area. In transverse
sections through the septum, narrow zones of small irregular myotest fibres can be
traced running from base to apex on both sides to meet dorsally. The structure of
the overlapping growth lamellae of Crenispirifer, which are formed as a result of
periodic mantle retractions, differs in some respects from that of the overlapping
growth lamellae described for S. walcotti. In Spiriferina the tip of the mantle lobe
after the initial withdrawal began to deposit a series of horizontal, overlapping,
organic and inorganic layers, but in Crenispirifer mantle regression was followed only
by deposition roughly normal to the posteriorly inclined regression plane which
preceded a return to normal primary and secondary shell deposition.
In summary, the shell structures of Crenispirifer, Punctospirifer and Spiriferina
cristata are closely comparable with the standard shell succession of Spiriferina wal-
cotti. No tertiary layer has been found in any Spiriferinacea.
(v) Reticulariacea
Unlike most forms assigned to the Spiriferidina, the Reticulariacea are generally
recognized by being relatively smooth-shelled with rounded cardinal extremities and
a short hinge line. Two species of Phricodothyris and one badly altered Martinia
were available for study.
Transverse sections through both valves of Phricodothyris sp. from the Finis Shale
(Pennsylvanian) of Texas reveal a remarkably well-preserved calcareous shell
succession comprising three distinct layers. The primary layer, which measures
up to 40 /mi in thickness, is normally massive but in certain areas the texture may
become porous, accompanied by the development of a fine lineation disposed normal
to the outer shell surface (PI. 25, figs. 3, 4). The surface micro-ornament of Phrico-
dothyris is distinctive and involves some disruption of the primary layer. It con-
sists of a series of regularly spaced concentric growth lamellae, each terminating
anteriorly in a row of fine double-barrelled spines. Unlike the hollow spines of
Spiriferina walcotti which connect with the shell interior by means of narrow canals,
240 SHELL STRUCTURE
those of Phricodothyris terminate within the primary layer. Invariably the spines
were broken, leaving only sunken bases which appear in longitudinal section as shal-
low, cigar-shaped hollows infilled with secondary material (PI. 25, fig. 3). The
general structure and possible function of the spines have already been discussed by
George (1932 : 529) and need not be considered further. Clearly the spines of any
one lamella were built up rapidly in localized patches of the circumferential genera-
tive zone of outer epithelium situated at the shell edge whilst neighbouring cells were
still involved in the deposition of the primary layer. As George points out, the
caecal prolongations of the mantle incorporated within the spines must have become
wholly dead matter before the secretion of the next succeeding lamella.
Since a tertiary layer is deposited over the greater part of the shell interior, the
secondary layer is comparatively thin, being about 25 /mi in depth overall. Close
to the valve margins, the secondary layer attains a thickness of nearer 40 /mi which
may indicate that the secondary layer secretory zone within the outer epithelium
widened with age. Fibres are orthodoxly stacked and measure about 12 to 15 /mi
in width (PL 25, fig. 4). The tertiary layer consists of straight-sided, vertically
stacked crystals which measure up to 15 /mi in width (PL 25, figs. 4, 5). The fabric
of the tertiary layer of Phricodothyris is strikingly similar to that of Gryphus even to
the extent of exhibiting a regular transverse depositional banding. The banding in
Phricodothyris sp. from the Finis Shale has an average periodicity of 1-5 /mi.
From around the periphery of each concentric growth lamella, a plane dips pos-
teriorly inwards to define the isochronous surface upon which the normal secretory
processes were interrupted (PL 25, fig. 3). Such zones of mantle retraction must have
been relatively narrow and confined to the outermost shell margins because regression
planes, defining the extent of the disruption, terminate within the secondary layer.
Although the zone of change-over from secondary to tertiary shell deposition is
located very close to the valve margins, as in Gryphus, the tertiary layer is not
affected by mantle regressions. As a result, there is no interdigitation of secondary
and tertiary layers as, for example, in Choristites.
The shell structure of Phricodothyris sp. from the Carboniferous Limestone Series
of Braidwood, Lanarkshire, was found to be identical to that of the American species.
The transverse tertiary layer banding, in this case, had an average periodicity of
1-2 /mi (PL 25, fig. 6).
The shell of the only specimen of Martinia that was available for study was badly
altered, but parts of the original fabric could still be recognized. The primary
layer had exfoliated, but parts of the secondary layer and a thick tertiary layer were
identified (PL 26, figs, i, 2).
(e) Thecospira
Thecospira is an unusual spire-bearing brachiopod, small but oyster-like in appear-
ance, with a variably deep, cup-shaped pedicle valve and relatively flat, lid-like
brachial valve. On the pedicle valve exterior there occurs a flattened cementation
scar. In recent years there has been some debate as to the precise systematic posi-
tion of Thecospira. Rudwick (1968 : 349) and Baker (1970 : 84) regarded it as an
SPIRIFERIDE BRACHIOPODA
241
periostracum -\ ^Vxr^^riS^^S^^^^^^r^— ^^ \base of pedicle
waive of
primary layer -*• \S<^^=^ ^ =^— -^— ' rihecospjra
} organic cement
molluscan
-shell
fragment
FIG. 19. Stylized section through part of the base of a pedicle valve of Thecospira cemented
to a molluscan fragment, showing the inferred relationships between the organic cement,
periostracum and primary layer.
aberrant strophomenide whereas Williams (ig68a : 48 and 1972) argued convincingly
in favour of a spiriferide identity for the genus. For precisely the same reasons as
those put forward by Williams (1972) I regard Thecospira as a member of the Spiri-
ferida.
The basic shell structure of Thecospira sp. collected from the St Cassian Beds
(Triassic) of Northern Italy closely resembles that of Spiriferina walcotti (Sowerby)
in that two calcareous shell layers are recognizable. An unusual aspect of growth of
Thecospira is the absence of any recognizable primary layer within the cementation
area of the pedicle valve. A complete specimen of Thecospira found cemented to a
bivalve fragment was sectioned normal to the plane of attachment. In the brachial
valve and in the convex, upstanding part of the pedicle valve, a primary layer mea-
suring up to 25 /u,m in thickness was identified (PI. 26, fig. 3), but below the attachment
area a zone about 15 /um wide, infilled mainly with sediment, was found interposed
between the flattened base of secondary layer fibres and the outer surface of the bi-
valve fragment (PI. 26, fig. 5). Presumably this narrow zone was occupied during
life by the organic adhesive which cemented the shell to the substrate (Text-fig. 19) .
Since the initial secretory phase of newly proliferated cells comprising the outer
mantle lobes of Recent brachiopods, both articulate and inarticulate, is known to
involve the exudation of mucopolysaccharide, it is considered highly likely that a
similar episode of organic deposition initiated the secretory regime of the thecospirid
mantle. In the pedicle valve of Crania anomala Miiller the cementing medium is
the outer mucopolysaccharide layer (Williams and Wright 1970 : 18). The pedicle
valves of living Thecideidina are presumably cemented to the substrate by a similar
deposit, for mucopolysaccharide has been found as an impersistent external coating
on the periostracum of Thecidettina barretti (Davidson) (Williams I97ib : 49). Since
within the attachment area of the pedicle valve of Thecospira no primary layer is
242
base of crus
SHELL STRUCTURE
cardinal process
socket
sunken adductor
. scars
: *-*\
.-"V
o °J- • .
g&£
sub-peripheral rim
FIG. 20. View of the general morphology of the brachial valve interior of
Thecospira (spiralium absent).
found, it seems likely that exudation of mucopolysaccharide and periostracum must
have been sustained over a relatively broad zone of the outer mantle lobe. The
suppression of the primary layer probably resulted from the persistent localized
deposition of an organic pad internal to the periostracum which acted as a sufficiently
rigid base and seeding sheet for the earliest-formed parts of secondary layer fibres.
Sections through both valves of Thecospira reveal that fibres of the secondary
layer are orthodoxly stacked and measure, on average, 15 /urn in width (PI. 26,
fig. 4). The interior of the brachial valve is not flat but sunken postero-medially in
the vicinity of the dorsal adductor muscle scars and raised marginally as a tuberculate
platform around the valve periphery (Text-fig. 20). A similar marginal tuberculate
zone, forming a sub-peripheral rim, is known to occur in some thecideidines, including
Moorellina granulosa (Moore) (Baker 1969 : 393). In radial sections through the
brachial valve of Thecospira, each tubercle is found to comprise a cylindroid core of
porous, non-fibrous calcite that protrudes above the surface of the rim and around
which secondary layer fibres are deflected laterally and inwardly (PI. 27, figs, i, 2,
3, 4). Tubercles with solid cores of this sort measuring up to 60 /u,m in diameter
closely resemble the pseudopuncta of certain Plectambonitacea and Gonambonitacea
(Williams 1970 : 340). Pseudopunctation is also characteristic of the laminar
shelled Strophomenida (Williams 1968% : 40), including all but the earliest David-
soniacea. Yet the 'pseudopunctation' of Thecospira is much closer to that described
for the spire-bearing Cadomella, the terebratulide Megerlia or more strikingly the
Jurassic thecideidine Moorellina than it is for any of the earlier strophomenide or
orthide stocks, for inwards of the sub-peripheral rim the tubercles are resorbed and
overlapped by later secondary shell material. Submerged tubercles considered to
have been functional peripherally are also found distributed sporadically within the
SPIRIFERIDE BRACHIOPODA
243
secondary shell succession of the pedicle valve of Thecospira. The tubercles of both
valves are not continuous with the primary layer as in Moorellina (Baker 1970 : 87),
but arise as modifications of pre-existing secondary layer fibres.
Both punctate and impunctate specimens of Thecospira were collected from the
same locality but whether or not they are variants of the same species has still to be
established. The puncta occur as sediment-filled canals measuring up to 40 /mi in
diameter which permeate the primary and secondary shell layers (PI. 27, figs. 4, 5).
Whereas fibres are deflected towards the shell interior around tubercle cores, they are
outwardly deflected around puncta.
In one punctate brachial valve of Thecospira, sections through the secondary
layer revealed a series of at least six transverse micritic bands up to 10 /mi thick
which ran parallel with the inner shell surface and were outwardly deflected by puncta
(PL 27, figs. 5, 6). The vertical spacing between bands is variable but generally
measures about 10 /zm to 20 /mi. Since the bands are most prominent towards the
inner surface and close to the valve periphery it is believed that they mark successive
levels of organic layers which were sandwiched within the normal calcareous succes-
sion. Such periodic reversals to wholly organic exudation may have corresponded
to temporary halts in shell growth, for fine overlapping growth lamellae do occur
around the periphery of gerontic specimens. However, in the particular shell section
which was found to exhibit a banded succession, individual growth lamellae could
not be directly correlated with the micritic layers.
The dorsal and ventral myotests of Thecospira are composed of modified secondary
layer fibres. The outlines of individual fibres are irregular and the lateral margins
of adjacent fibres often occur welded together (PL 28, fig. i). In the pedicle valve
the arcuate anterior borders of the two ventral diductor scars are raised above
the valve floor to form an anteriorly inclined overhang (PL 28, fig. 2). This semi-
recumbent ridge is considered to have developed in response to the stresses placed on
the overlying outer epithelium by the most anterior part of the ventral muscle base.
It is evident that the angle between the shell surface and the estimated disposition
of the long axes of muscle fibres in that region would approach more closely the most
efficient maximum of 90 degrees (Text-fig. 21).
V. STRUCTURE OF THE BRACHIDIUM AND INFERRED DISPOSITIONS
OF THE LOPHOPHORE IN SPIRIFERIDA
(a) Structure of spiralia
Within the order Spiriferida, the size, shape and disposition of the spiral brachidium
that, in all probability, supported the lophophore are highly variable. In one of the
earliest-known spiriferides, Protozyga elongata Cooper, support for the lophophore is
rudimentary and consists simply of a pair of short prongs which extend anteriorly
from a median connecting band, the jugum (Williams & Wright 1961 : 158, fig. 4g).
When sectioned transversely close to the jugum, the calcareous outgrowths of P.
elongata are found to be extremely slender. Sections through either branch reveal
244
SHELL STRUCTURE
adductor
I
post.
FIG. 21. Stylized longitudinal section through both valves of Thecospira showing the
inferred dispositions of adductor and diductor muscles, and the U-shaped profiles of the
spiral lamellae (b.v. - brachial valve, p.v. - pedicle valve).
outlines of only 25 to 30 secondary layer fibres stacked orthodoxly in rows up to five
deep (PI. 28, fig. 3). This compares with well over 1000 individual fibre outlines
arranged in rows up to about 40 fibres deep occurring in any one transverse section
through a spiral lamella of a mature Spiriferina. Due to secondary recrystalliza-
tion, the precise attitude of the fibres comprising the brachidium of P. elongata could
not be established with any degree of certainty.
In slightly younger representatives of the same stock, such as Protozyga exigua
Hall which appeared in the late Ordovician (Rockland Formation), the anterior
prolongations of the jugum extend further as a pair of narrow ribbons each coiling
for up to one convolution, as a planispire aligned parallel to the median plane.
Planispiral coiling of the brachidium in a plane parallel to the median plane is repeated
and increased to 3 or 4 convolutions in the smooth Dayiacean, Cyclospira, although it
is reported to be ajugate.
A number of late Ordovician and early Silurian genera characterized by the
development of spiralia with medially directed apices are considered to have evolved
from the primitive protozygid stock. These include Catazyga, Zygospira, Idiospira
and Glassia. However in the majority of later Atrypacea, including Atrypa, the
spiralia became reorientated dorso-medially with apices directed towards the mid-
line of the brachial valve.
In almost all remaining Spiriferida, the apices of spiralia are directed laterally but
in some genera, such as Koninckina, Thecospira and Cyrtina, the spiralia were directed
SPIRIFERIDE BRACHIOPODA 245
ventrally or postero-ventrally. In a number of athyrididines, postero-median
growth and bifurcation of the jugum resulted in the development of a pair of recurved
arms (accessory lamellae) which were positioned adjacent to the innermost lamellae
of the primary coils of the spiralia. In Diplospirella and certain allied genera
continued growth of the accessory lamellae gave rise to a pair of intercoiled accessory
spires which extended as far as the apices of the primary ones.
The structure and growth of the spiralia of Spiriferina walcotti, which may be
considered as typical of many Spiriferida, have already been described (see p. 206).
Secondary layer fibres which are generated in a zone running around the sharp outer
edges of the spiralium are secreted on both sides of the spiral lamella and each fibre
is seen to follow an arcuate path away from the apex of the spire which, it is believed,
corresponds to a segment of a logarithmic spiral. In cross section, the convex keels
of fibres arch outwards in both directions from a median plane (Text-fig. 7b) . Similar
double-sided spiral lamellae have been identified in the early atrypaceans Catazyga
headi (Billings) (PI. 28, fig. 4), Idiospira thomsoni Davidson (PI. 28, figs. 5, 6), the
dayiacean Dayia navicula (Sowerby) (PI. 29, fig. i), the early retziidine Rhyncho-
spirina maxwelli Amsden (PI. 29, fig. 2), the cyrtiacean Ambocoelia umbonata (Conrad)
(PI. 29, figs. 3, 4) and the spiriferaceans Theodossia hunger fordi (Hall) (PI. 29, fig. 5),
and Spirifer trigonalis Martin (PI. 29, fig. 6). Spiralia belonging to the aforemen-
tioned genera, when sectioned, present a similar profile to that described for Spiri-
ferina . The outward edge of each lamella is pointed whereas the inner edge is generally
truncated. The thickest part of the lamella is around its mid-region. On either
side of a line running from roughly the middle of the blunt inner edge to the fine outer
edge, the convex keels of small regularly stacked secondary layer fibres, generally
less than 10 /am in width, arch outwards. Narrow spines, which outwardly deflect
localized groups of fibres, project from the median-facing side of the spiralia of Idio-
spira (PL 28, figs. 5, 6). Presumably these spines performed a similar function, and
were deposited in a similar manner, to those projecting from parts of the spiralia of
Spiriferina.
The structure of the spiralia of certain Athyrididina differs markedly from the
structure of those previously described. Instead of exhibiting a double-sided growth
pattern, sections through the athyrididine spiralia reveal deposition of secondary
layer fibres on only the median-facing side of each lamella. As spiralia were generally
embedded in rock matrix enclosed within both valves of each specimen, it was not
possible to view surfaces of lamellae directly to establish the precise orientation of
fibres. However, this could be deduced by preparing two vertical transverse sec-
tions which cut tangentially through the edges of the spiralia (Text-fig. 22a), once on
its anterior side and once on its posterior side, and then noting the relative disposi-
tion of fibres in each section (Text-fig. 22b). In the anterior section, fibres are
directed dorsally whereas in the posterior section they are directed ventrally. Pro-
gressive changes in the cross-sectional outlines of fibres between the dorsal and ventral
extremities of each sectioned lamella are considered to reflect corresponding changes
in the orientation of fibres from one end to the other. The observed pattern of
sectioned fibres corresponds to that occurring in one half of a sectioned 'double-sided'
spiral, such as in Spiriferina, and clearly reflects for each individual skeletal unit a
246
SHELL STRUCTURE
a
FIG. 22. a. Generalized plan view of an athyrid spiralium. The two lines of section are
located on either side of the axis of the spiralium. Consecutive coils of each spire are
not planar but curved so as to appear outwardly concave, b. Lateral view of a spire
showing the lines of section and the growth direction of fibres. In the anterior section
(i) fibres are directed dorsally whereas in the posterior section (2) fibres are directed
ventrally.
SPIRIFERIDE BRACHIOPODA 247
similar pattern of fibre growth. Since each spiral lamella grew by accretion of secon-
dary layer material on only the median-facing side, it is evident that resorptive pro-
cesses must have operated on the apical side. Although the arrangement of growth
and resorption faces is contrary to what might be expected, a steady overall increase
in the size of the spiralia can still be achieved dependent on the attitude of the
lamellae. Consecutive coils of the spiralia of many athyrididines are not planar but
curved so as to appear outwardly concave. In consequence the terminal faces of
fibres deposited on the median-facing side of both spires are directed outwards away
from the median plane.
'Single-sided' spiral lamellae have been identified in the athyridaceans Composita
ambigua (Sowerby) (PL 30, figs. I, 2), Athyris spiriferoides (Eaton) (PI. 30, fig. 3),
Diplospirella wissmani (Munster) (PL 30, fig. 4) and Anisactinella quadriplecta
(Miinster) (PL 30, fig. 5), as well as other more distantly related forms including
Koninckina leonhardi (Wissman) (PL 30, fig. 6 ; PL 31, fig. i), Amphiclina amoena
Bittner (PL 31, fig. 2) and Thecospira sp. (PL 31, fig. 3).
Compared with secondary layer fibres found elsewhere in the brachial valve, those
comprising the spiralia of Diplospirella and Anisactinella are abnormally small. On
both primary and accessory lamellae fibres measure, on average, 12 //.m in width as
opposed to 60 /Am width on the floor of each brachial and pedicle valve. The acces-
sory lamellae as well as the primary lamellae of Diplospirella and Anisactinella are
characterized by one-sided growth, although the convex keels of fibres arch out-
wards towards the apices of the spiralia and not medially as on the main spires
(Text-fig. 23). Since each coil of the accessory lamellae is situated lateral to the
corresponding coils of the primary lamellae it is evident that two non-depositional
faces are in opposition to one another throughout. Both primary and accessory
lamellae are fimbriate but as yet it has not been established whether the fimbriae
occur on only the anterior-facing edges of the spires, as in Spiriferina. Nevertheless,
presumably they served a similar purpose. The spinous outgrowths are found to
project from only the median-facing side of primary lamellae and the apical side of
accessory lamellae. On the opposite sides of both sets of lamellae, spine bases are
resorbed along with the long exposed trails of fibres comprising the rest of that surface.
Although parts of the calcareous lophophore supports of some living Terebratulida
are known to be fimbriate, the relationships between fimbriae and adjacent soft
tissues, as well as modes of secretion, have yet to be established. At high magnifica-
tions, the distal extremities of spines projecting from the spiralia of Diplospirella are
noticeably jagged, resembling in shape the thorns of a rosebush. Such products of
mineral deposition are totally foreign to mature outer epithelial cells which are
normally involved in the build-up of more conventional secondary shell material,
but some elements of spicular skeletons, known to be secreted within the lophophore
and mantle of a number of living Terebratulida, bear resemblance to the jagged parts
of spines. Spicules, however, are found only within the inner epithelium and con-
nective tissue where, according to Williams (i968b : 280), they develop within
scleroblasts. Assuming that the primary and accessory spiralia of Diplospirella
were ensheathed by connective tissue and inner epithelium of the lophophore, the
'raw materials' for spicule formation were certainly available. However, to become
19
248 SHELL STRUCTURE
embedded within the secondary shell succession of the spiralia, spines secreted by
mesoderm or endoderm must first have pierced the outer epithelial lining, which
seems unlikely. More probably, the spines were secreted by specialized outer epi-
thelial cells reminiscent in structure and function of those which must have con-
tributed to the formation of solid tubercle cores or taleolae in other genera.
a.
c.
b.
FIG. 23. a. View of the spiral brachidium of Diplospirella wissmani showing the disposition
of the primary and accessory lamellae, b. Transverse section through both valves and
spiralium of Diplospirella. c. More detailed view of a transverse section through a
primary (left) and accessory (right) lamella of Diplospirella showing the shape and
stacking of secondary layer fibres.
In Koninckinacea, the brachidium consists of a pair of double spires with the
principal pair arising on a simple crural process from which they diverge at a sharp
angle. A jugum is formed by the anterior extension and union of the crural processes,
and the accessory spires which originate on this connecting band lie ventral to the
main pair and are co-extensive with them. The apices of both pairs of spiralia are
directed towards the lateral slopes of the pedicle valve (Text-fig. 243., b).
By comparison with the giant-sized fibres which make up the general shell succes-
sion of Koninckina, the fibres composing the spiral brachidia are small (on average
SPIRIFERIDE BRACHIOPODA
249
primary lamella
fresorbed face
uppermost)
accessory lamella {
(mosaic uppermost!
Distribution of jayerg
primary
secondary
tertiary
FIG. 24. Plan view (a) and anterior view (b) of a generalized koninckinacean brachial
valve interior showing the disposition of the spiralium (including growth vectors of
fibres) and the distribution of shell layers.
250 SHELL STRUCTURE
about 7 jLtm wide). The size range of those fibres in the brachial structures, however,
compares more favourably with that of fibres occurring in other articulates such as
Retzia sp., even from the same horizon, in which mature secondary layer fibres are
about 10 jum wide. As previously mentioned, fibres composing the spiralia of Diplo-
spirella and related genera are about a fifth the size of those occurring elsewhere in
both valves.
Transverse sections through the arms of the koninckinacean spiralium reveal some-
thing of the size, shape and stacking of its constituent fibres (PL 30, fig. 6 ; PL 31,
fig. i). Fibre outlines associated with such structures appear much more conven-
tional than those of the rest of the shell in that they display easily recognizable keels
and saddles. This configuration provides a convenient means of recognizing growth
surfaces, since the convex surfaces of keels always face towards a depositional surface.
In Koninckina the regular overlapping habit of fibres in sections through spires
indicate that deposition took place on the dorsal surface of the primary lamellae and
on the ventral surface of the accessory lamellae. The two inner opposing faces of the
primary and accessory lamellae were thus surfaces of resorption.
Whilst examining specimens of Amphiclina, a disarticulated pedicle valve was
found which retained part of a primary lamella still located in almost the exact
position of growth (see PL 16, fig. 3). The ventral-facing (resorbed) side was upper-
most. Nevertheless, despite the lack of any recognizable mosaic, it was possible to
plot the long axes of exposed trails of fibres, and by using them as growth vectors,
thereby reconstruct an overall brachidial growth pattern. The fibres comprising
each spiral lamella curve obliquely across its surface (PL 31, fig. 2 ; Text-fig. 24),
from inner to outer edge, like those of Spiriferina, in such a way that their trails
inscribe a spiral curve (probably logarithmic) on which the terminal parts of fibres
are directed progressively further away from the apex of the spire to produce a
gradual peripheral expansion along the outer edge of every whorl. On the outer
half of the ventral side of the primary lamella, the oblique outlines of exposed
trails are replaced by a much finer lineation aligned at right angles to the outer edge
of the lamella. At high magnification (PL 31, fig. 4), the lineation appears as a
series of narrow troughs and ridges, on average 4 /mi wide. No comparable features
have, as yet, been recognized on any other articulate brachiopod so that the mode of
formation and function of such lineations are problematical. However, it seems likely
that they may be the product of some unusual resorptive process. Both primary
and accessory lamellae of koninckinaceans are fimbriate, in the sense that fine spines
project obliquely from their depositional surfaces and cause the trails of surround-
ing fibres to be gently deflected around them.
The form of spiral brachidium that is characteristic of Thecospira differs markedly
from that found in all other Spiriferida. A comprehensive description of the macro-
scopic morphology of the thecospirid brachidium has been given by Rudwick
(1968 : 337) and needs only to be referred to briefly. From the base of the cardinal
process, a pair of short crura extends anteriorly to join with, and support, the ven-
trally directed spiralia. According to Rudwick, a simple transverse jugum connects
the proximal ends of the crura. Each lamella is U-shaped in section (Text-fig. 21)
with the dorsal branch being thicker and about twice as long as the ventral one. The
SPIRIFERIDE BRACHIOPODA 251
two branches close inwardly on the side closest to the spiral axis, so that the groove
faces laterally outwards.
At the microscopic level, the dorsal limb of the U is found to comprise small,
orthodox secondary layer fibres which measure, on average, 8 /mi in width, but the
lower limb is essentially non-fibrous (PI. 32). The convex keels of fibres in the upper
limb face ventrally into the groove and towards the lower limb. In cross section the
profile of the lower limb is undulating in such a manner as to suggest, in three
dimensions, that it is fluted parallel or subparallel to the length of the spire. This
interpretation is further supported by the occurrence of a series of concentrically
banded zones, each about 20 /xm wide, which coincide with the undulations (PL 31,
fig. 5) . The narrowest diameters of the concentric bands are so fine that it seems most
likely that the zones terminate distally as sharp points. If this is the case, then the
undulations may be considered as sections through laterally fused spinose out-
growths which project obliquely outwards from the lower limb of the U-shaped groove.
At the junction of the upper and lower limbs the secondary layer fibres are bent
round through 180 degrees so that their curved saddles come to rest against the
inner surface of the lower limb. At the opposite, outer edge of the upper lamella,
fibres are deflected around spine bases. Since peripheral spine bases have been
recognized in every section through the spiralia of Thecospira that has been examined,
they must be densely distributed in that area. Fibres of the upper limb are also
disturbed within a variably wide non-fibrous zone which runs from midway along the
ventral surface, obliquely inwards, and terminates on the dorsal surface just above
the junction of the upper and lower limbs of the U. In some sections, the enclosed
accretions are fairly massive, but in others they are much less prominent. Small
concentrically banded zones have been recognized within some of these, and may
represent parts of embedded spines (PL 31, fig. 6). Since no similar deposits have
been recognized within the brachidia of other fossil or Recent brachiopods, they are
extremely difficult to interpret mainly because any sediment-free fragments of
spires on which a three-dimensional reconstruction could be based are lacking.
Once suitable specimens are found a more enlightened explanation may be forth-
coming. At present, the only objects that can be considered as likely to give rise
in section to such amorphous shapes are forms of spicules such as are found within
the lophophore and mantle of some living Terebratulida.
Sections cut through the middle of spiral coils reveal transverse outlines of fibres
but tangential sections show successions of long trails of fibres. If the shape of
sectioned fibres can be taken as a rough guide to their orientation, then it is evident
that the fibres comprising the upper limbs of the grooved spiral lamellae are aligned
sub-parallel to the curved edges of the spiralia. This is essentially the same pattern
as that observed in more conventional spiralia (equiangular spiral growth), thus it is
assumed that the spiral lamellae of Thecospira grew in the same way.
(b) Inferred dispositions of the spiriferide lophophore
The relationships between skeletal supports and brachial appendages have been
investigated in living Terebratulida with a view to establishing the most likely
252 SHELL STRUCTURE
dispositions of the lophophore in extinct Spiriferida. In living long-looped forms,
such as Macandrevia, the lateral arms of the plectolophous lophophore are supported
by the ascending and descending branches of the calcareous loop (Text-fig. 25).
a. b.
FIG. 25. Ventral (a) and lateral (b) views of the plectolophe of Macandrevia
and its calcareous supports.
They bear a double brachial fold, two rows of paired filaments, and are served by
two brachial canals (Williams 1956 : 263). As both canals are tucked in between the
ascending and descending branches of the loop, it is of interest to note that opposing
faces of the calcareous support of each side-arm bear surfaces of resorption while
those on outward-facing sides bear surfaces of growth which exhibit a well-developed
secondary shell mosaic. When viewed in section, the convex keels of fibres com-
prising the ascending and descending branches are seen to arch outwards away from
each other (Text-fig. 26). Since exactly the same relationship exists between fibres
comprising the primary and accessory lamellae of Diplospirella and Koninckina it
seems reasonable to assume that the brachial canals of these extinct genera must also
have occupied a median position between the two lamellae. Thus in more normal
athyrididines in which the accessory lamellae are greatly reduced or non-existent,
the brachial canals of the lophophore must have been situated on the apical sides of
the primary lamellae. By using the one-sided distribution of spinose outgrowths
(fimbriae) as a means of determining the position of the lophophore, Rudwick (igGoa :
375) arrived at the same conclusion. Since the double-sided spiral lamellae of most
other Spiriferida also bear spines on their median-facing sides, Rudwick considered
that they too possessed brachial systems orientated with the main body of the
lophophore situated on the apical sides of lamellae. Certainly in those forms which
SPIRIFERIDE BRACHIOPODA
descending branch
of loop
central coil of plectolophe
side arm
FIG. 26. Stylized transverse section through part of the plectolophe of Macandrevia showing
the relationship of soft parts to the growth and resorbed surfaces of the ascending and
descending branches of the loop. (After Williams, 1956 : text-fig. 4.)
show the greatest swelling in the median regions of lamellae, such as Spirifer trigonalis,
the greater part of the swelling is on the apical side. In addition, since the width of
the lamella is greatly reduced in its inner half, behind the swelling, partial resorption
must have operated on some parts of that side. Thus the disposition of the brachial
canals can still be correlated with areas of resorption on double-sided lamellae. In
Thecospira, the inferred disposition of the lophophore, as deduced by this method,
contradicts the hitherto perfectly plausible views expressed by previous authors (e.g.
Rudwick 1968 : 335, fig. 36). Placed against the surface undergoing resorption the
main body (or brachial axis) of the lophophore would have rested on the dorsal
surface of the broad fibrous limb of the U-shaped lamellae, and not within the
groove. The precise orientations of the brachial groove (s) and filaments which
comprised the food-gathering apparatus of the lophophore are less easy to decipher
and, regrettably, ultrastructural studies relating to brachidial structure shed little
new light on this tantalizing problem. Whether the spiriferid brachidium supported
a simple spirolophe (Rudwick ig6oa, b) with only a single set of filaments and one
food groove, or a doubled set of appendages, the deuterolophe (Williams 1956 : 270,
1960 : 515 ; Williams & Wright 1961 : 149-176) is still open to discussion. However,
since spiral brachidia may be divided into two separate groups based principally on
the recognition of single or double-sided growth patterns, it may well have been that
a genuine diversity in brachial structure existed. By analogy with the side-arms of
long-looped terebratulides, the twin coils of spiralia belonging to forms such as
Diplospirella and Koninckina may have supported a double row of paired filaments.
If so, the single spiral coils of other athyrididines may also have provided a lesser
support for the same system. On the other hand, spiral brachidia exhibiting double-
sided growth may have supported single spirolophes, especially in those forms which
appear to be without a jugum as in a number of cases.
254 SHELL STRUCTURE
VI. CONCLUSIONS
Recent research has shown that, in all probability, the secretory regime of articulate
and inarticulate brachiopods has always involved at least three fundamental opera-
tions. Certainly in all forms of living brachiopods yet studied at the ultrastructural
level (including Craniacea, Rhynchonellida, Terebratulida and Thecideidina) deposi-
tion of an outer mucopolysaccharide cover and an inner fibrillar triple-layered
membrane has preceded secretion of the predominantly mineralized part of the exo-
skeleton. Presumably these two organic constituents comprised part, if not all, of
the periostracal covering to the calcareous exoskeleton of the primitive Protozyga-
like stock which is considered as ancestral to all Spiriferida (Text-fig. 27). If simi-
larities in shell structure between Protozyga and contemporary Rhynchonellida are
of any significance in indicating a common ancestor, then the earliest representatives
of the Spiriferida almost certainly had only two calcareous shell layers. By the
beginning of Silurian times, however, the secretory regime of most Spiriferida had
developed further giving rise to three main types of skeletal fabric. The first,
which includes the Atrypacea, Dayiacea, early Athyridacea and some early Spiri-
feracea, was characterized by being impunctate and possessing a variably thick
tertiary prismatic layer in addition to the standard primary and secondary layers.
The second group, including the Retziacea and Suessiacea, which were both punctate,
possessed only primary and secondary shell layers. The third group, including the
Cyrtiacea and remaining Spiriferacea, was the most conservative and secreted
impunctate shells consisting only of primary and secondary layers.
Throughout the remainder of spiriferide evolution such clear-cut distinctions were
not maintained. As far as is known all Atrypidina possessed three calcareous shell
layers, but, unlike the Meristellidae, few later Athyridacea appear to have secreted
a tertiary layer. Cleiothyridina is the only known Carboniferous athyrid to have
done so. The Triassic Diplospirellinae are characterized by an exceedingly coarse
fibrous secondary layer, but no additional tertiary layer deposit like that found in
contemporary and younger Koninckinacea is present. The exoskeletal succession
of the Retziacea was remarkably stable from Silurian to Triassic times. The
impunctate Cyrtiacea and punctate Suessiacea were equally conservative. Con-
siderable variation is shown, however, within the remainder of the Spiriferidina. As
far as is known, nearly all Devonian Spiriferacea possessed only primary and secon-
dary layers but later stocks show greater diversity. Punctation was developed in at
least two stocks, the Spiriferinacea and Syringothyridae, and tertiary prismatic layers
are found in some Carboniferous Spiriferidae and Brachythyrididae. In the Reti-
culariacea, too, a tertiary layer was deposited. Tubercles with non-fibrous cores
grew peripherally in punctate and impunctate Thecospiridae and some Koninckina-
cea, but away from the shell edge they ceased to become functional and were sub-
merged within later-formed parts of the calcareous succession. In this respect, such
rod-like bodies differ from the pseudopuncta of Strophomenida with which they have,
in the past, been compared and no special phylogenetic significance is attached to
their appearance.
From the foregoing account, it is evident that despite the great diversity of form
that has accompanied spiriferide evolution, there were few radical changes in
SPIRIFERIDE BRACHIOPODA
255
Primitive Protozyga-like stock
mucopolysaccharide
triple unit membrane
tubercles
puncta
crystalline
primary layer
fibrous
secondary layer
prismatic
tertiary layer
FIG. 27. Inferred phylogeny of the skeletal successions of the Spiriferida.
secretory regime. In Spiriferina walcotti (Sowerby), which has been selected as a
standard model for spiriferide shell deposition, and in living Terebratulida, the struc-
ture of the primary and secondary layers and the finer details of shell punctation are
very similar. Clearly the spiriferide outer epithelium was little different from that
found in most living articulates. Even in forms possessing a tertiary layer, the
nature of the outer epithelium may be reasonably inferred on account of a similar
layer occurring in the living terebratulide Gryphus vitreus (Born). Indeed, all basic
256 SHELL STRUCTURE
mantle secretory processes that are known to have operated in spire-bearing Brachio-
poda, from their appearance in the Ordovician to their extinction in the Jurassic,
were successful enough to have been retained by living articulate brachiopods of one
form or another.
VII. ACKNOWLEDGEMENTS
I am greatly indebted to Professor Alwyn Williams, Queen's University of
Belfast, for his guidance and encouragement whilst this work was in progress, for
critically reading the manuscript and for his willingness to discuss the subject at all
times. Additional discussion on many aspects of the work with Dr C. H. C. Brunton
of the British Museum (Natural History) was invaluable and rewarding.
To Mr R. Reed and the technical staff of the Faculty of Science Electron Micro-
scopy Unit, Queen's University of Belfast, I am most grateful for instruction in the
preparation and examination of the material referred to in this publication, and for
the production of electron micrographs figured herein.
For the loan or gift of fossil material I am most grateful to Dr W. D. I. Rolfe of
the Hunterian Museum, University of Glasgow, Professor Alwyn Williams, Dr A. D.
Wright and Mr Ian Mitchell of the Department of Geology, Queen's University of
Belfast, and Dr C. H. C. Brunton.
Finally, I gratefully acknowledge the award of a research studentship from the
Natural Environment Research Council.
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SPIRIFERIDE BRACHIOPODA 257
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brachiopod Cadomella. Palaeontology, London, 15 : 405-411, pis. 76-78.
COOPER, G. A. 1954. Unusual Devonian brachiopods. /. Paleont., Tulsa, 28 : 325-332,
pis. 36, 37-
— — 1956. Chazyan and related brachiopods. Smithson. misc. Collns, Washington, 127: i-
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COPPER, P. 1967. The shell of Devonian Atrypida (Brachiopoda) . Geol. Mag., London,
104 : 123-131, pis. 5, 6.
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Brachiopoda. Palaeontogr. Soc. (Monogr.), London, 1, (3) : i-ioo, pis. 1-18.
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GEORGE, T. N. 1932. The British Carboniferous reticulate Spiriferidae. Q. Jlgeol. Soc. Lond.,
88: 516-575, pis. 31-35-
1933- Principles in the classification of Spiriferidae. Ann. Mag. nat. Hist., London, (10)
11 : 423-456.
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1894. An introduction to the study of the genera of Palaeozoic Brachiopoda.
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tissue. Comp. Biochem. Physiol., London, 30 : 209-224.
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MACKINNON, D. I. i97ia. Perforate canopies to canals in the shells of fossil Brachiopoda.
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thesis (unpubl.), Queen's University of Belfast.
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1968. The feeding mechanisms and affinities of the Triassic brachiopods Thecospira
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geol. Soc. Lond., 81 : 595-666, pis. 38-41.
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Meded., Leiden, 41 : 1-82, pis. 1-14.
258
SHELL STRUCTURE
WILLIAMS, A. 1956. The calcareous shell of the Brachiopoda and its importance to their
classification. Biol. Rev., Cambridge, 31 : 243-287.
— 1960. Correspondence (The feeding mechanisms of spire bearing fossil brachiopods) .
Geol. Mag., London, 97 : 514-516.
— igdSa. Evolution of the shell structure of articulate brachiopods. Spec. Pap. Palaeont.,
London. 2 : 1-55, 24 pis.
— I968b. A history of skeletal secretion among articulate brachiopods. Lethaia, Oslo,
1 : 268-287.
— 1970. Origin of laminar shelled articulate brachiopods. Lethaia, Oslo, 3 : 329-342.
— i97ia. Comments on the growth of the shell of articulate brachiopods. In Dutro,
J. T., jr (Ed.), Paleozoic perspectives : a paleontological tribute to G. Arthur Cooper.
Smithson. Contr. Paleobiol., Washington, 3 : 47-67, pis. 1-3.
— I97ib. Scanning electron microscopy of the calcareous skeleton of fossil and living
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& ROWELL, A. J. 1965. Brachiopod anatomy, morphology. In Moore, R. C. (Ed.),
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INDEX
An asterisk (*) denotes a figure.
Acanthothiris, 197
accessory lamellae, 245
adductor scars, dorsal, 203
ventral, 201-3
Aloxite, 191
Ambocoelia umbonata, 229, 245 ; pi. 17,
figs 2, 3 ; pi. 29, figs 3, 4
Ambocoeliidae, 229
amino-acids, 193
Amphiclina, 226-8, 250
amoena, 225, 247 ; pi. 15, fig. 6 ; pi. 16,
fig. 3 ; pi. 31, figs 2, 4
suessi, 225
Anisactinella, 224-5, 247
quadriplecta, 223-4, 247 '• pi- T5> ng- 2 »
pi. 30, fig. 5
articulation, 210-2
Athyridacea 190, 221-5, 254
Athyrididina 190, 221-8, 245, 247
spiralium 246*
Athyris 222-4
spiriferoides 222, 247 ; pi. 12, figs 5, 6 ;
pi. 30, fig. 3
Athyrisinacea, 220
Atrypa, 215-7, 2I9*. 22%> 244
reticularis, 215 ; pi. 7, fig. 6
sp. 215 ; pi. 8 ; pi. 9, figs i, 2
Atrypacea, 190, 212-8, 220, 244, 254
Atryparia, 215, 218
Atrypidina, 212-20, 229, 254
Atrypina hami, 215
Bowlditch Quarry, 192
brachial valve, 203-5
brachidium, 190, 206-9
structure of, 190, 243-51, 248*
Brachyspirifer, 234
Brachythyrididae, 237, 254
Brachythyris sp., 238 ; pi. 24, figs i, 2
Cadomella, 225, 242
davidsoni, 225
moorei, 225
caecum, 196
cardinalia, 204*
Catazyga, 212, 214-5, 218, 220, 244
headi, 213, 245 ; pi. 7, figs 1-3
wmzygu, ziz, z 14-^5, zio, ZZL
headi, 213, 245 ; pi. 7, figs
fig- 4
pi. 28,
INDEX
259
Chonetidina, 225
Choristites, 237-8, 240
mosquensis, 237 ; pi. 23
classification of Spiriferida, 190
Cleiothyridina, 223, 234, 254
deroissii, 223 ; pi. 13, figs 2-4
Coelospira saffordi, 218, 220 ; pi. 10, figs i, 2
Composita, 222, 224
ambigua, 222-3, 247 > pi- J3> fig- J > pi- 3°.
figs i, 2
Costispiriferidae, 235
Crania anomala, 241
Craniacea, 254
Crenispirifer sp., 238-9 ; pi. 25, figs i, 2
Crurithyris sp., 229-30 ; pi. 17, figs 4-6
cardinal process, 230
Cyclospira sp., 218, 244 ; pi. 9, figs 3, 4
Cyrtia, 232
exporrecta, 229 ; pi. 17, fig. i
Cyrtiacea, 229-30, 254
Cyrtiinae, 229
Cyrtina, 230-2, 232*, 233*, 244
ventral median septum and tichorhinum,
231*
alpenensis, 230 ; pi. 18, fig. i
sp., 230-1 ; pi. 18, figs 2, 3
Cyrtinidae, 230
Davidsoniacea, 242
Dayia, 218, 220
navicula, 218, 234, 245 ; pi. 9, figs 5, 6 ;
pi. 29, fig. i
Dayiacea, 190, 212, 218-20, 254
Delthyridae, 233
Delthyris, 232-3
saffordi, 233 ; pi. 18, fig. 4
dental ridges, 210
depositional banding, transverse, 223
Desquamatia, 218
subzonata, 215
Diplospirella, 223-5, 245> 247~8, 250, 252-3
wissmanni, 223, 247, 248* ; pi. 13, figs 5,
6 ; pi. 14 ; pi. 15, fig. i ; pi. 30, fig. 4
Diplospirellinae, 254
diurnal banding, 220
' double-sided ' growth of spiralia, 190,
245-7
electron microscope, 190-1
endopunctate brachiopoda, 196
Eospirifer, 229, 232
Eospiriferinae, 229
Epon Araldite, 191
Euryspirifer, 234
Fimbrispirifer, 234
functional considerations, muscle attachment
areas, 205
gerontic forms, 196
Glassia, 244
Gonambonitacea, 242
growth lamellae, 199
growth lines, concentric, 198-201
Gruenewaldtia, 215, 218
Gryphus, 214, 217-8, 223, 228, 234, 238, 240
vitreus, 190, 213, 255
Hallina, 212
Hemithiris psittacea, 235-7
Hodder's Quarry, Timsbury, 192
hollow spines, 196-8
Homeospira evax, 220-1 ; pi. 10, fig. 4
Howellella, 232, 234
Howittia, 234
Hustedia radialis, 220-1 ; pi. 10, fig. 5 ;
pi. ii, figs 3, 4
Hysterolites, 234
Idiospira, 214-5, 220, 244-5
thomsoni, 214, 245 ; pi. 7, figs 4, 5 ; pi. 28,
figs 5. °
' jigsaw-puzzle ' shell fabric, 214, 218, 234
jugum, 206, 209, 243, 248, 250, 253
keel, 227, 227*, 250
Kerpina, 218
Koninckella liassina, 225
triassina, 225
Koninckina, 225-8, 226*, 227*, 244, 248, 250,
253
leonhardi, 225, 247 ; pi. 15, figs 3-5 ;
pi. 16, figs i, 2, 4-6 ; pi. 30, fig. 6 ;
pi. 31, fig. i
Koninckinacea, 190, 221, 225-8, 248-50,
249*, 254
Kozlowskiellina velata, 233-4 >' pi- I^> ngs 5>
6 ; pi. 19
lamellae, spiral, 206-7, 207*, 208* ; see
spiralia
Licharewiinae, 235
lineation, 250
Lissatrypidae, 214-5
Lobothyris punctata, 194
Lo-Kitt, 191
lophophore, 190-1, 206, 243 ; see plectolophe
inferred dispositions of, 190, 209, 251-3
260
INDEX
Macandrevia, 252, 252*, 253*
Magasella sanguinea, 237
mantle retraction, 198-201, 202*
Martinia sp., 239-40 ; pi. 26, figs i, 2
median septum, 201, 203
Megerlia, 242
Meristella atoka, 221-2; pi. n, figs 5, 6;
pi. 12, figs 2-4
Meristellidae, 254
Meristina tumida, 221-2 ; pi. 12, fig. i
microscope, electron, 190-1 ; see Stereoscan
microvilli, 195
Mimatrypa, 215, 218
Moorellina granulosa, 242-3
morphology of shell, 192
mucopolysaccharide, 241-2, 254
Mucrospirifer sp., 234 ; pi. 20, figs i, 2
muscle attachment areas, 196, 201-5
muscle system, 205, 244*
myotest, 203
Neospirifer camaratus, 237 ; pi. 22, fig. 2
Notosaria, 215, 224, 231, 232*, 234, 236
nigricans, 201
orthide stocks, 242
Paraspirifer, 234
pedicle valve, 201-3
perforate canopies of puncta, 196
periostracum, 190, 192-3, 195, 200, 241-2
Phricodothyris sp., 239-40 ; pi. 25, figs 3-6
phylogeny of skeletal successions, 255*
plasmalemma, 195, 200*
Plectambonitacea, 208, 242
plectolophe, 252, 253*
preparation of specimens, technique, 191
primary layer, 190, 193-5
thickness of, 193*
Protozyga, 212, 214, 243, 254
elongata, 212-3, 243-4 ; pi. 6, fig. 5 ;
pi. 28, fig. 3
exigua, 244
'Protozy go-like' shells of Middle Ordovician,
212, 254
pseudopunctation, 242
punctation, puncta, 196-7, 197*
Punctospirifer scabricosta, 238-9 ; pi. 24,
figs 4-6
Queensland, Permian of, 194
Radstock Shelf, 191-2
resorption, surfaces of, 207-8
Reticulariacea, 190, 229, 239-40, 254
Retzia sp., 220-1, 250 ; pi. 10, fig. 6 ; pi. n,
figs i, 2
Retziacea, 220, 254
Retziidina, 220-1
Rhynchonellida, 190, 194-5, 199, 203, 226-7,
227*, 233, 236, 254
Rhynchospirina maxwelli, 220-1, 245 ; pi. 10,
fig. 3 ; pi. 29, fig. 2
saddle, 227, 227*, 250
scleroblasts, 247
secondary layer, 190, 195-6, 200*, 210
shell layers, calcareous, in brachiopods, 190
flexures in, 199
fluctuations in deposition of, 201, 202*
shell structure of Spiriferide brachiopoda,
187-258
of Spiriferina walcotti, 191-212
of other spiriferida, 212-43
shell succession, 192-6, 197*
' single-sided ' growth of spiralium, 190, 247
Siphonotretacea, 198
skeletal fabric, 189
Skenidioides, 222
sockets, 210, 212
Sowerbyella, 208
specimen preparation, technique of, 191
Spinatrypa sp., 215, 218
tubular spines of, 216, 217*
Spinatrypina, 218
spine canals, 197*
spines, hollow, 196-8, 197*, 216, 217*
on spiral lamellae, 247-8
Spinella, 234
Spinocyrtia sp., 234-5 ; pi. 20, figs 3, 4
Spinocyrtiidae, 235
spiralia, 190-1, 206, 209*, 244*, 249*
spines on, 209
structure of, 243-51
Spirifer trigonalis, 210, 237-8, 245, 253 ;
pi. 22, figs 3-6 ; pi. 29, fig. 6
Spiriferacea, 190, 229, 232-8, 254
Spiriferida, 187-258
Spiriferidae, 254
Spiriferide brachiopoda, shell structure, 187-
258
Spiriferidina, 229-40
classification, 229
Spiriferina, 190, 212-3, 216, 220-1, 233, 239,
244-5, 247, 250
'cristata var. octoplicata' ' , 238-9 ; pi. 24,
fig- 3
rostrata, 206
INDEX
261
walcotti, 189-90, 191-212, 238-9, 241,
255 ; pis 1-5 ; pi. 6, figs 1-4
articulation, 210-2
brachial valve, 203-5
brachidium, 206-9
diagnosis, 191
functional considerations of muscle
attachment areas, 205
growth lines, concentric, 198-201
hollow spines, 196-8
mantle retraction, 198-201
morphology of shell, 192
muscle attachment areas, 201-5
pedicle valve, 201-3
periostracum, 192-3
primary layer, 193-5
punctation, 196
secondary layer, 195-6
shell succession, 192-6
spines, hollow, 196-8
spiralia, 206-9, 245
Spiriferinacea, 229, 238-9, 254
Spiriferinella cristata, 238 ; see " Spiriferina
cristata var. octoplicata "
spondylium simplex, 222
' Stereoscan ', 191, 218, 223, 237
Strophomenida, 225, 254
spines, 198
Subansiria, 235
sp., 194
Suessia, 230
Suessiacea, 229-32, 254
Suessidae, 230
Syringospira, 236*, 236-7
prima, 235 ; pi. 21, fig. 6 ; pi. 22, fig. i
Syringothyridae, 235, 254
Syringothyris cuspidata, 235 ; pi. 20, figs 5, 6
taleolae, 207*, 208
teeth, 210, 211*, 212
Tenticospirifer cyrtiniformis, 235-7 '• P^ 2I>
figs 3-5
Terebratalia transversa, 204
Terebratulida, 190-1, 194-5, *99. 2O3> 22I»
226-7, 227*. 233- 236, 247. 251- 254-5
tertiary layer, 190, 234, 238, 255
Thecideidina, 241-2, 254
Thecidellina barretti, 241
Thecospira, 240-4, 241*, 242*, 244*, 250-1,
253
sp., 247 ; pi. 26, figs 3-5 ; pi. 27 ; pi. 28,
figs i, 2 ; pi. 31, figs 3, 5, 6 ; pi. 32
Thecospiridae, 190, 254
Theodossia hungerfordi, 235, 245 ; pi. 21,
figs i, 2 ; pi. 29, fig. 5
tichorhinum, 230-1
Timsbury, 192
tonofibrils, 203
tubercles, peripheral, 190
ventral adductor muscle fields, 201-3
Waltonia inconspicua, 222
Zygospira, 212-5, 244
modesta, 213 ; pi. 6, fig. 6
DAVID I. MACKINNON
Department of Geology
UNIVERSITY OF CANTERBURY
CHRISTCHURCH
NEW ZEALAND
Accepted for publication 18 September 1973
PLATE i
All figures are scanning electron micrographs of the shell.
Spiriferina walcotti (Sowerby)
Lower Lias, Bowlditch Quarry, Radstock, Somerset
FIG. i. . View of the external surface of a valve showing the fine radial lineations (running
obliquely from bottom to top) on which are superimposed concentric growth lines (running
obliquely from left to right). 6658878. x 650. (pp. 193, 199)
FIG. 2. More general view of concentric growth lines on the external surface of a valve and a
number of broken, anteriorly inclined, spine bases. Same specimen, BB 58878. x 60. (pp. 193,
197, 199)
FIG. 3. Detailed view of a prominent longitudinal groove which occurs directly in front of a
spine base. The spine base would be located directly below the micrograph. BB 58884.
X 1250. (p. 193)
FIG. 4. Detailed view of parallel grooves situated behind and deflected around a spine base.
The spine base would be located directly above the micrograph. Same specimen, BB 58884.
XI200. (p. 193)
FIG. 5. Section through the primary layer showing the twofold division into outer granular
(top) and inner, more massive (bottom) parts. Secondary layer fibres are just visible at the
bottom of the micrograph. Same specimen as PI. 2, fig. 5, BB 58887. x 1450. (p. 194)
FIG. 6. View of the secondary shell mosaic on a valve interior showing the smooth, spatulate
outlines of terminal faces. Same specimen as PL 2, fig. i, BB 58885. x 1200. (p. 195)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE i
20
PLATE 2
All figures are scanning electron micrographs of the shell.
Spiriferina walcotti (Sowerby)
Lower Lias, Bowlditch Quarry, Radstock, Somerset
FIG. i . View of the internal surface of a valve showing a punctum formed by the deflection
of secondary layer fibres. Same specimen as PL i, fig. 6, BB 58885. x 700. (p. 196)
FIG. 2. General view of the external surface of a valve showing a punctum with damaged
perforate canopy. BB 58880. x 1200. (p. 196)
FIG. 3. More detailed view of the perforate canopy in fig. 2, showing canals. BB 58880.
X6ooo. (p. 196)
FIG. 4. General view of a ventral muscle scar showing straight grooves of the adjuster area
(left) and the more flabellate impression of the diductor area (top) . Anterior ridge at the bottom.
Same specimen as PL 4, figs. 1-3, BB 58896. xc. 60. (p. 201)
FIG. 5. Radial section through primary and secondary layers showing a slight flexure.
Although secondary layer fibres close to the primary layer (top left) exhibit long trails, those
caught up within the flexure are transversely sectioned. Same specimen as PL i, fig. 5, BB 58887.
XI350. (p. 199)
Bull. BY. Mus. nat. Hist. (Geol.) 25, 3
PLATE 2
PLATE 3
Spiriferina walcotti (Sowerby)
Scanning electron micrograph montage of a shell from the Lower Lias, Hodder's Quarry,
Timsbury, Somerset. Radial section through a brachial valve margin showing two major
overlapping shell units. The regression planes are directed posteriorly inwards from the
primary layer and separate the bulk of the secondary layer fibres from the series of vertically
stacked, flat or gently curved lamellae of primary shell material which mark consecutive stages
in the retreat of the mantle edge. The second and most recent overlapping unit (bottom of
micrograph) is located right at the periphery of the valve. BB 58890. x 250. (pp. 196, 199)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 3
PLATE 4
All figures are scanning electron micrographs of the shell.
Spiriferina walcotti (Sowerby)
Lower Lias, Bowlditch Quarry, Radstock, Somerset
FIG. i. Detail of the posteriorly inclined slope of an anterior ridge around a ventral muscle
scar showing the development of long exposed trails and the encroachment of myotest (bottom
left). Same specimen as PI. 2, fig. 4, BB 58896. x 240. (p. 201)
FIG. 2. General view of the anterior part of a ventral muscle scar showing the deeply im-
pressed furrows. Same specimen, BB 58896. X&5- (p. 201)
FIG. 3. Detailed view of a deeply impressed furrow within a ventral adjuster scar and
surrounding fibres which are orthodoxly stacked. Same specimen, 665 8896. x 220. (p. 201)
FIG. 4. Section through the ventral median septum showing a zone of small, gnarled,
irregularly stacked fibres comprising part of the ventral adductor myotest. BB 58901. x 850.
(p. 203)
FIG. 5. More detailed view from the centre of fig. 4. BB 58901. x 3400. (p. 203)
FIG. 6. Section through the ventral median septum cut close to the umbo showing the
overlap of a later secondary layer deposit upon a postero-dorsal edge. 6658902. X 750.
(p. 203)
Bull. BY. Mus. nat. Hist. (Geol.) 25, 3
PLATE 4
PLATE 5
All figures are scanning electron micrographs of the shell.
Spiriferina walcotti (Sowerby)
Lower Lias, Bowlditch Quarry, Radstock, Somerset
FIG. i. General view of anterior (right) and posterior (left) dorsal adductor scars. Anterior
to the top of the micrograph. BB 58898. x 25. (p. 204)
FIG. 2. View of a fracture surface within an anterior dorsal adductor scar showing the finely
granular myotest underlain by conventional secondary layer fibres. Same specimen, BB 58898.
X 130. (p. 204)
FIG. 3. View of two corrugated ridges comprising the cardinal process. Each ridge is com-
posed of tightly interlocking secondary layer fibres. BB 58903. x 690. (p. 204)
FIG. 4. View of the deeply impressed dorsal adductor muscle scar showing a series of narrow
stalks which project towards the umbo. Same specimen, BB 58903. x 130. (p. 204)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 5
PLATE 6
All figures are scanning electron micrographs of the shell.
Spiriferina walcotti (Sowerby)
Lower Lias, Bowlditch Quarry, Radstock, Somerset
FIG. i. General view of a tooth showing a dental ridge projecting within the delthyrial cavity
(bottom) and a large bulbous swelling. BB 58906. X25. (p. 210)
FIG. 2. Detailed view of the abraded ends of secondary layer fibres comprising the bulbous
ridge. Same specimen, BB 58906. x 1200. (p. 210)
FIG. 3. Section through the distal end of a tooth showing the regular variation in the disposi-
tion of secondary layer fibres. Same specimen, BB 58906. x 300. (p. 212)
FIG. 4. More detailed view of part of fig. 3. BB 58906. x 750. (p. 212)
Protozyga elongata Cooper
FIG. 5. Ordovician (Lower Bromide Formation), i mile west of Dolese Brothers Crusher,
Bromide, Oklahoma. Transverse section through the secondary layer showing irregular outlines
of fibres ; exterior of valve towards the bottom. Same specimen as PL 28, fig. 3, BB 58918.
X 2600. (p. 212)
Zygospira modesta (Say)
FIG. 6. Ordovician (Richmond Group), road cutting 0-3 mile north of Vaughan's Gap,
US 100, near Nashville, Tennessee. Transverse section through the secondary layer in the
pedicle valve showing diamond-shaped profiles of fibres ; exterior of valve towards the bottom
right corner. BB 58920. x 1300. (p. 213)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 6
PLATE 7
All figures are scanning electron micrographs of the shell.
Catazyga headi Billings
Ordovician (Richmond Group), Adana Co., near Winchester, Ohio.
Same specimen as PL 28, fig. 4, BB 58921
Fig. i. Section of the secondary layer showing the characteristic diamond-shaped outlines
of fibres, x 1400. (p. 213)
FIG. 2. Section showing the junction of the secondary (bottom) and tertiary (top) layers in
a pedicle valve ; exterior of valve towards the bottom. x 1300. (p. 213)
FIG. 3. Section close to a valve margin showing the development of a wedge of primary shell
sandwiched between earlier and later secondary shell deposits. X 630. (p. 214)
Idiospira thomsoni (Davidson)
Ordovician (Craighead Limestone), Girvan, Ayrshire.
Same specimen as PI. 28, figs. 5-6, BB 58922
FIG. 4. Detail of sectioned secondary layer fibres showing well-developed keels and saddles.
X56oo. (p. 214)
FIG. 5. Section through a secondary layer showing partial fusion of adjacent fibres due to
secondary recrystallization. x 2400. (p. 214)
Atrypa reticularis (Linne)
FIG. 6. Silurian (Wenlock Limestone), Much Wenlock Railway, Shropshire. Section through
the primary and secondary shell layers ; primary layer located at top left corner. BB 58923.
X2450. (p. 215)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 7
PLATE 8
All figures are scanning electron micrographs of the shell.
Atrypa sp.
Devonian (Hamilton Group), New York
FIG. i. Transverse section through the pedicle valve showing the characteristic outlines and
mode of stacking of secondary layer fibres. Same specimen as PI. 9, fig. i, BB 58924. x 280.
(P- 215)
FIG. 2. Transverse section through the pedicle valve showing the outward deflection of
secondary layer fibres around a (submerged) gonadal pit ; exterior of valve towards the top.
Same specimen, BB 58924. x 280. (p. 215)
FIG. 4. General view of section through a valve margin showing a series of overlapping
growth lamellae. Same specimen, BB 58924. x 70. (p. 216)
FIG. 5. More detailed view of part of fig. 4, showing the interdigitation of primary and
secondary layers in the vicinity of overlapping growth lamellae ; shell exterior towards the top.
Same specimen, BB 58924. x 270. (p. 216)
FIG. 6. Transverse section through a pedicle valve showing the development of a tertiary
layer which is succeeded inwardly (bottom) by a later secondary shell deposit. Same specimen,
6658924. X28o. (See also Text-fig. 12.) (p. 216)
FIG. 3. General view of part of the inner surface of a ventral valve showing the development of
gonadal pits ; lateral shell edge situated towards the right. BB 58928. x 30. (p. 215)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 8
PLATE 9
All figures are scanning electron micrographs of the shell.
Atrypa sp.
Devonian (Hamilton Group), New York
FIG. i. Section through a pedicle valve showing the junction between the secondary layer
and the ventral myotest (bottom). Same specimen as PL 8, figs. 1-2, 4-6, BB 58924. x 280.
(See also Text-fig. 12.) (p. 217)
FIG. 2. View of the surface topography within the ventral adductor muscle scar showing the
irregular outlines of individual crystals. 6658925. x 1400. (p. 217)
Cyclospira sp.
Ashgillian (Killey Bridge beds), exposed in the bank of Little River,
200 yards east of Slate Quarry Bridge, 2j miles ENE of Pomeroy,
Co. Tyrone, Northern Ireland. BB 58931
FIG. 3. Section through a pedicle valve showing diamond-shaped outlines of secondary
layer fibres, x 1200. (p. 218)
FIG. 4. Section through a pedicle valve showing depositional banding within the tertiary
layer below a ventral muscle scar, x 2400. (p. 218)
Dayia navicula (Sowerby)
Ludlovian (Dayia Shales), Park Farm Quarry, Onibury, Shropshire.
BB 58933. (See also PL 29, fig. i)
FIG. 5. Section through a pedicle valve showing the junction between the secondary (top
left) and tertiary (bottom right) layers. x 1200. (p. 218)
FIG. 6. Section through a pedicle valve showing a more general view of the secondary layer
and part of the tertiary layer, x 600. (p. 218)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 9
21
PLATE 10
All figures are scanning electron micrographs of the shell.
Coelospira saffordi (Foerste)
Silurian, Brownsport Formation, Western Tennessee. BB 58932
FIG. i. Section through a pedicle valve showing the shape and stacking of secondary layer
fibres. x 1 200. (p. 220)
FIG. 2. Section through a pedicle valve showing the development of a tertiary layer. Silici-
fied parts of the shell stand out. x 250. (p. 220)
Rhynchospirina maxwelli Amsden
FIG. 3. Devonian (Haragan Formation), White Mound, Murray County, Oklahoma. Section
through a valve showing the distribution of the primary and secondary layers. Secondary
layer fibres arch outwards around a punctum. Same specimen as PL 29, fig. 2, BB 58936.
X650. (p. 220)
Homeospira evax (Hall)
FIG. 4. Silurian (Waldron Formation), Waldron, Indiana. Section through a valve showing
the disposition of the primary and secondary layers. Secondary layer fibres arch outwards
around a punctum. BB 58935. x 1200. (p. 220)
Hustedia radialis (Phillips)
FIG. 5. Carboniferous (Arden Limestone), Arden, Lanarkshire. Section through the primary
and secondary shell layers. The primary layer is strongly lineated normal to the primary/
secondary layer boundary. Secondary layer fibres arch outwards around a punctum. Same
specimen as PL n, figs. 3-4, BB 58937. x 1200. (p. 220)
Retzia sp.
FIG. 6. Triassic (St Cassian beds), i km east of Rif. Pralongia-Htt. (Pralongia Refuge Chalet),
Pralongia Ridge, 4-5 km ESE of Corvara in Badia, Italy. Section through the primary and
secondary layers showing two puncta which coalesce inwardly within the secondary layer.
Same specimen as PL u, figs. 1-2, BB 58939. x 1200. (pp. 220, 221)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 10
PLATE ii
All figures are scanning electron micrographs of the shell.
Retzia sp.
Triassic (St Cassian beds), i km east of Rif. Pralongia-Htt. (Pralongia Refuge Chalet),
Pralongia Ridge, 4-5 km ESE of Corvara in Badia, Italy.
Same specimen as PI. 10, fig. 6, BB 58939
FIG. i. Section through the primary layer showing a fine transverse depositional banding.
The shell exterior is located beyond the top right corner. x 2400. (p. 220)
FIG. 2. Section through secondary layer fibres showing their general outlines and mode of
stacking. Some depositional banding can be recognized, x 6200. (p. 220)
Hustedia radialis (Phillips)
Carboniferous (Arden Limestone), Arden, Lanarkshire.
Same specimen as PI. 10, fig. 5, BB 58937
FIG. 3. Section through the primary and secondary layers showing the bulbous distal end
of an infilled punctum, which is separated from the outer sedimentary coating by a uniformly
narrow zone. Presumably this space was occupied by a calcite canopy. x 1200. (p. 221)
FIG. 4. Detailed view of a distal end of a punctum infilled by small crystals of iron pyrites
in the form of pyritohedra. The space above the distal end of the punctum was, presumably,
occupied by a calcite canopy, x 2400. (p. 221)
Meristella atoka Girty
Devonian (Haragan Formation), White Mound, Murray County, Oklahoma. BB 58940
FIG. 5. Section through the primary and secondary shell layers. x 2300. (p. 221)
FIG. 6. Section through the secondary and tertiary shell layers. X 650. (p. 221)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE i i
PLATE 12
All figures are scanning electron micrographs of the shell.
Meristina tumida (Dalman)
FIG. i. Silurian, Gotland. Section through the secondary layer (bottom right) and very
thick tertiary layer. 6658944. x 68. (p. 221)
Meristella atoka Girty
Devonian (Haragan Formation), White Mound, Murray County, Oklahoma. BB 58943
FIG. 2. Transverse section through brachial valve showing the irregular skeletal fabric of an
adductor myotest. x 1350. (p. 222)
FIG. 3. General view of a transverse section through the cardinal plate (top) and supporting
median septum, x 58. (p. 222)
FIG. 4. Transverse section through the cardinal plate showing the development of a highly
porous skeletal fabric on top of the normal secondary layer succession. It is probably a dorsal
adjuster myotest. xnyo. (p. 222)
Athyris spiriferoides (Eaton)
Devonian (Wanakah Shale), Canandaiga Lake, New York State.
BB 58948. (See also PI. 30, fig. 3)
FIG. 5. Section through the primary and secondary shell layers. x noo. (p. 222)
FIG. 6. More detailed view of a section through the secondary layer showing the regular
shape and stacking of constituent fibres. x 2200. (p. 222)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 12
PLATE 13
All figures are scanning electron micrographs of the shell.
Composita ambigua (Sowerby)
FIG. i. Carboniferous (Calmy Limestone), Carluke, Lanarkshire. Section through the
primary and secondary shell layers. BB 58951. x 1250. (pp. 222, 223) (See also PI. 30,
figs. 1-2.)
Cleiothyridina deroissii (Leveille)
Carboniferous (Blackbyre Limestone), Brockley, Lesmahagow, Lanarkshire. BB 58952
FIG. 2. Section through the secondary layer showing the general shape and stacking of
constituent fibres, x 6500. (p. 223)
FIG. 3. Section through the tertiary layer showing prominent transverse depositional
banding, x 2500. (p. 223)
FIG. 4. Section through valve showing an alternation of secondary and tertiary layers. Shell
interior beyond the top left corner. X625. (p. 223)
Diplospirella wisstnani (Miinster)
Triassic (St Cassian beds), Alpe de Specie (formerly Seelandalpe),
2-5 km NW of Carbonin (formerly Schluderbach), n km NE of Cortina
d'Ampezzo, Trentino, Italy
FIG. 5. Transverse section through the primary and secondary shell layers. Same specimen
as PI. 30, fig. 4, BB 58956. x 1300. (p. 223)
FIG. 6. View of the secondary shell mosaic on the internal surface of the brachial valve.
Same specimen as PI. 14, figs. 1-3 and PL 15, fig. i, BB 58959. x 650. (p. 223)
Bull. Dr. Mus. nat. Hist. (Geol.) 25, 3
PLATE 13
PLATE 14
All figures are scanning electron micrographs of the shell.
Diplospirella wissmani (Miinster)
Triassic (St Cassian beds), Alpe de Specie (formerly Seelandalpe),
2-5 km NW of Carbonin (formerly Schluderbach), n km NE of
Cortina d'Ampezzo, Trentino, Italy
FIG. i. General view of the secondary shell mosaic located in front of the dorsal median
septum. Anterior shell edge located beyond the top left corner. Same specimen as PL 13,
fig. 6 and PI. 15, fig. i, BB 58959. x 65. (p. 223)
FIG. 2. General view of the interior of a brachial valve in which the secondary shell mosaic
can still be discerned. Same specimen, BB 58959. x 27. (p. 223)
FIG. 3. View of anterior margin of a dorsal adductor myotest showing the breakdown of the
secondary shell mosaic. Anterior shell edge located beyond the bottom left corner. Same
specimen, BB 58959. x 280. (p. 224)
FIG. 4. Transverse section through a dorsal adductor myotest showing the irregular outline
of fibres. The shell interior is located at the bottom of the micrograph. BB 58957. x 650.
(p. 224)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 14
PLATE 15
All figures are scanning electron micrographs of the shell.
Diplospirella wissmani (Miinster)
FIG. i. Triassic (St Cassian beds), locality as PI. 14. View of the posterior margin of a
dorsal adductor myotest showing the overlap of long-exposed trails by a cluster of very small
fibres. Anterior shell edge located beyond the bottom left corner. Same specimen as PL 13,
fig. 6 and PI. 14, figs. 1-3, BB 58959. x 280. (p. 224)
Anisactinella quadriplecta (Miinster)
FIG. 2. Triassic (St Cassian beds), i km east of Rif. Pralongia-Htt. (Pralongia Refuge Chalet),
Pralongia Ridge, 4-5 km ESE of Covara in Badia, Italy. Section through the primary and
secondary shell layers. Same specimen as PI. 30, fig. 5, BB 58960. x 1250. (p. 225)
Koninckina leonhardi (Wissman)
Triassic (St Cassian beds), 0-5 km SE of Rif. Pralongia-Htt. (Pralongia Refuge Chalet),
4 km SE of Corvara in Badia, Italy
FIG. 3. Transverse section through the primary and secondary shell layers. BB 58962.
X 2600. (p. 225)
FIG. 4. General view of the outer shell surface showing a fine radial striation (running from
bottom to top) with a few fine concentric growth lines (running from left to right). BB 58966.
X 240. (p. 226)
FIG. 5. General view of the diamond-shaped terminal faces comprising the secondary shell
mosaic. Anterior shell edge located beyond the left edge of the micrograph. Same specimen
as PI. 16, fig. 4, BB 58963. x 280. (p. 226)
Amphiclina amoena Bittner
FIG. 6. Triassic (St Cassian beds), Alpe de Specie (formerly Seelandalpe), 2-5 km NW of
Carbonin (formerly Schluderbach), n km NE of Cortina d'Ampezzo, Trentino, Italy. View of
diamond-shaped terminal faces comprising the secondary shell mosaic on the brachial valve
interior. Same specimen as PL 16, fig. 3, BB 58967. x 660. (p. 227) (See also PL 31, figs. 2, 4.)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 15
PLATE 16
All figures are scanning electron micrographs of the shell.
Koninckina leonhardi (Wissman)
Triassic (St Cassian beds), 0-5 km SE of Rif. Pralongia-Htt. (Pralongia Refuge Chalet),
4 km SE of Corvara in Badia, Italy
FIG. i . Longitudinal section through secondary layer fibres showing a prominent depositional
banding. Same specimen as PI. 30, fig. 6 and PI. 31, fig. i, BB 58961. x 1300. (p. 227)
FIG. 6. Longitudinal section through a brachial valve showing a regrowth of some secondary
layer fibres upon a tertiary layer deposit. Shell interior at the top ; anterior shell edge beyond
the left edge of the micrograph. Same specimen, BB 58961. x 270. (p. 228)
FIG. 2. Oblique section through the secondary layer showing depositional banding.
BB 58965. x 1300. (p. 227)
FIG. 4. View of the tertiary layer fabric on top of a dome-shaped swelling on the interior
surface of a brachial valve. Same specimen as PL 15, fig. 5, BB 58963. x 750. (p. 228)
FIG. 5. Transverse section through a brachial valve showing secondary and tertiary layers.
BB 58964. x 650. (p. 228;
Amphiclina amoena Bittner
FIG. 3. Triassic (St Cassian beds), Alpe de Specie (formerly Seelandalpe), 2-5 km NW of
Carbonin (formerly Schluderbach), n km NE of Cortina d'Ampezzo, Trentino, Italy. General
view of dome-shaped swelling on the interior of the brachial valve showing spiral grooves and
gonadal pits. A fragment of a primary lamella of the spiralium can be seen adhering to the
surface in the foreground. Same specimen as PL 15, fig. 6, BB 58967. xc. 80. (pp. 227, 250)
(See also PL 31, figs. 2, 4.)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 16
PLATE 17
All figures are scanning electron micrographs of the shell.
Cyrtia exporrecta (Wahlenberg)
FIG. i. Silurian, Coalbrookdale, Shropshire. View of a section through the secondary layer
showing the shape and stacking of constituent fibres. BB 58970. x 5800. (p. 229)
Ambocoelia umbonata (Conrad)
Devonian (Wanakah Shale), Canandaiga Lake, New York State.
Same specimen as PI. 29, figs. 3, 4, BB 58971
FIG. 2. Section through a valve periphery showing a series of overlapping growth lamellae
with interdigitation of primary and secondary shell layers. x 600. (p. 229)
FIG. 3. Section through the secondary layer showing the characteristic shape and stacking
of fibres. x 2400. (p. 229)
Crurithyris sp.
Carboniferous (Finis Shale), Texas. BB 58972
FIG. 4. View of the interior of a brachial valve showing the standard secondary shell mosaic.
X55°- (P- 230)
FIG. 5. General view of the umbonal region of a brachial valve showing cardinal process,
crura, sockets and faint adductor muscle scars, x 26. (p. 230)
FIG. 6. More detailed view of part of fig. 5, showing the tuberculate nature of the cardinal
process. x 64. (p. 230)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 17
22
PLATE 18
All figures are scanning electron micrographs of the shell.
Cyrtina alpenensis Hall & Clarke
FIG. i. Devonian, Rockport, Alpena County, Michigan. Section through the primary and
secondary shell layers. Puncta penetrate both layers. BB 58973. x 1300. (p. 230)
Cyrtina sp.
Devonian (Hackberry Stage), Bird Hill, 5 miles WSW of Rockford, Iowa
FIG. 2. Transverse section through a pedicle valve showing the median septum with parti-
tioned tichorhinum (outlined for clarity) . Part of one dental plate is visible in the bottom right
corner. 6658975. X 115. (p. 230)
FIG. 3. Transverse section through a pedicle valve showing the development of a myotest
(diductor) on the lower flanks of the median septum. BB 58976. x 1200. (p. 231)
Delthyris sqffordi (Hall)
FIG. 4. Silurian (Brownsport Formation), western Tennessee. Section through the secondary
layer showing the characteristic shape and stacking of fibres. BB 58977. x 2500. (p. 233)
Kozlowskiellina velata (Amsden)
Devonian (Haragan Formation), White Mound, Murray County, Oklahoma.
Same specimen as PI. 19, figs. 1-4, BB 58978
FIG. 5. Section through the primary and secondary shell layers, x 2600. (p. 233)
FIG. 6. Section through the secondary layer showing the shape and stacking of constituent
fibres. Shell interior located beyond the top of the micrograph, x 1400. (p. 233)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 18
• <v 'f/t , ^iiy^'.,^r 4^Gi, ^ *
PLATE 19
All figures are scanning electron micrographs of the shell.
Kozlowskiellina velata (Amsden)
Devonian (Haragan Formation), White Mound, Murray County, Oklahoma.
Same specimen as PL 18, figs. 5, 6, BB 58978
FIG. i. General view of a transverse section through both valves. The area squared off
within the brachial valve (top) is shown in fig. 2. xc. 75. (p. 233)
FIG. 2. Transverse section through part of a brachial valve. The squared-off area, taking
in a submerged crus, is reproduced in fig. 3. x 130. (p. 233)
FIG. 3. Detailed view of a section through a submerged crus showing the shape and stacking
of secondary layer fibres, x 1300. (p. 233)
FIG. 4. Transverse section through a pedicle valve showing part of the ventral diductor
myotest (lower middle) which is succeeded (upwards) by small orthodoxly stacked secondary
layer fibres. The interior is located beyond the top of the micrograph, x 720. (p. 233)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 19
PLATE 20
All figures are scanning electron micrographs of the shell.
Mucrospirifer sp.
Devonian, Killians, Presque Isle Co., Road 634, 0-2 miles north of Presque/Alpena County line,
Michigan. BB 58979
FIG. i. Section through the primary and secondary shell layers, x 3000. (p. 234)
FIG. 2. Section through the secondary layer showing the shape and stacking of fibres.
x 2800. (p. 234)
Spinocyrtia sp.
Devonian, Killians, Presque Isle Co., 1-3 miles west of Leroy, Michigan. BB 58984
FIG. 3. Section through the primary and secondary shell layers. x 2200. (p. 234)
FIG. 4. Section through the secondary layer showing the shape and stacking of fibres.
X6ooo. (p. 235)
Syringothyris cuspidata (Martin)
Carboniferous (Upper Visean), Staffordshire. BB 58985
FIG. 5. Section through a partially recrystallized secondary layer with fibres outwardly
deflected (bottom right) around a punctum. x 2400. (p. 235)
FIG. 6. More general view of fig. 5. Shell exterior is located beyond the bottom of the
micrograph, xiiyo. (p. 235)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 20
PLATE 21
All figures are scanning electron micrographs of the shell.
Theodossia hungerfordi (Hall)
Devonian (Hackberry Stage), Tile Yard, Rockford, Iowa.
Same specimen as PL 29, fig. 5, BB 58986
FIG. i. Section through secondary layer fibres comprising a spiral lamella, showing their
characteristic shape and stacking, x 2600. (p. 235)
FIG. 2. Section through part of the tertiary layer, x 640. (p. 235)
Tenticospirifer cyrtiniformis (Hall & Whitfield)
Devonian (Hackberry Stage), Tile Yard, Rockford, Iowa. BB 58987
FIG. 3. Section through the primary and secondary shell layers, x 1400. (p. 235)
FIG. 4. Section through the secondary layer showing the characteristic shape and stacking
of fibres, x 2500. (p. 235)
FIG. 5. Section through a ventral myotest of a pedicle valve showing the grossly modified
skeletal fabric. x 1500. (p. 236)
Syringospira pritna Kindle
FIG. 6. Devonian (Percha Formation), New Mexico. Section through the primary and
secondary shell layers. Same specimen as PL 22, fig. i, BB 58988. x 600. (p. 236)
Bull. BY. Mus. nat. Hist. (Geol.) 25, 3
PLATE 21
PLATE 22
All figures are scanning electron micrographs of the shell.
Syringospira prima Kindle
FIG. i . Devonian (Percha Formation) , New Mexico. Section through the j unction of 'blisters'
showing a uniformly crystalline zone between partitions composed of secondary layer fibres.
Same specimen as PL 21, fig. 6, BB 58988. x 640. (p. 236)
Neospirifer cameratus (Morton)
FIG. 2. Pennsylvanian (La Salle Limestone), quarry south of U.S. Highway 6, i-i miles east
of La Salle, Ohio. Section through the primary and secondary shell layers. BB 58994. x 1300.
(P- 237)
Spirifer trigonalis Martin
Carboniferous (Douglas Main Limestone), Lower Limestone Group, Brockley,
Lanarkshire
FIG. 3. Section through a brachial valve of a young specimen showing thin primary, secon-
dary, and tertiary layers. Same specimen as PL 29, fig. 6, BB 58992. x 1300. (p. 237)
FIG. 5. Section through a brachial valve showing an alternating sequence of secondary and
tertiary layers. Same specimen, BB 58992. x 280. (p. 237)
FIG. 4. Section through a thick tertiary layer showing some interdigitation with secondary
layer material. BB 58991. x 145. (p. 237)
FIG. 6. Section through a ventral myotest showing narrow irregular fibrous outlines which
inwardly succeed a tertiary layer (top). Same specimen, BB 58991. x 1200. (p. 237)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 22
PLATE 23
All figures are scanning electron micrographs of the shell.
Choristites mosquensis Buckman
Carboniferous, Moscow. BB 58995
FIG. i. Section through the primary and secondary shell layers, x 2550. (p. 238)
FIG. 2. Section through the secondary layer showing the characteristic shape and stacking of
fibres, x 2500. (p. 238)
FIG. 3. Section through the tertiary layer showing the prominent transverse depositional
banding. The shell interior is located beyond the top of the micrograph, x 2500. (p. 238)
FIG. 4. More detailed view of the prominent transverse depositional banding within the
tertiary layer showing the development of several finer bands within each major one. x 6200.
(P- 238)
FIG. 5. Section showing interrligitation of secondary and tertiary layers. x 260. (p. 238)
FIG. 6. Section through a ventral myotest showing the irregular outlines of fibres which
succeed the normal secondary layer succession, x 1250. (p. 238)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 23
PLATE 24
All figures are scanning electron micrographs of the shell.
Brachythyris sp.
Carboniferous, Kildare, Ireland. BB 58997
FIG. i. Section through the secondary layer. x 2400. (p. 238)
FIG. 2. Section through the tertiary layer showing several vertically stacked crystals. Shell
interior located beyond the top left corner. x 1200. (p. 238)
'Spiriferina cristata, var. octoplicata'
FIG. 3. Carboniferous (Carboniferous Limestone Series), Ashfell, England. Section through
the secondary layer showing the outward deflection of fibres around a punctum. 6659001.
X 1250. (p. 239)
Punctospirifer scabricosta North
Carboniferous (Carboniferous Limestone Series), England. BB 58999
FIG. 4. Section through the primary and secondary shell layers. x 1200. (p. 239)
FIG. 5. Section through the secondary layer showing the characteristic shape and stacking
of fibres. x 2600. (p. 239)
FIG. 6. Section through the secondary layer showing the outward deflection of fibres around
a punctum. x 1300. (p. 239)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 24
PLATE 25
All figures are scanning electron micrographs of the shell.
Crenispirifer sp.
Pennsylvanian (La Salle Limestone), quarry south of U.S. Highway 6, i-i miles east of
La Salle, Ohio. BB 58998
FIG. i. Section through the primary and secondary shell layers, x 1350. (p. 239)
FIG. 2. Section through the secondary layer showing the outward deflection of fibres around
a punctum. x 620. (p. 239)
Phricodothyris sp.
Carboniferous (Finis Shale), Texas. BB 59002
FIG. 3. Section through the primary (bottom), secondary and tertiary (top left) shell layers.
The primary layer accommodates a hollow spine base (now infilled) which is located upon an
overlapping growth lamella. A wedge of primary shell material extends within the secondary
layer but does not affect the tertiary layer, x 600. (pp. 239, 240)
FIG. 4. Section through the primary (bottom), secondary, and tertiary (top) layers, showing
a transverse depositional banding within the tertiary layer. x 550. (pp. 239, 240)
FIG. 5. Section through the secondary and tertiary layers showing a prominent transverse
depositional banding within the tertiary layer. x 2200. (p. 240)
FIG. 6. Carboniferous (Carboniferous Limestone Series), Braid wood, Lanarkshire. Section
through the tertiary layer showing depositional banding identical to that found in the American
species of Phricodothyris. BB 59003. x 1400. (p. 240)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 25
23
PLATE 26
All figures are scanning electron micrographs of the shell.
Martinia sp.
Carboniferous, Kildare, Ireland. BB 59004
FIG. i. Section through the secondary layer showing indistinct outlines of fibres, x 2400.
(p. 240)
FIG. 2. Section through part of the tertiary layer. Shell interior located beyond top left
corner, x 650. (p. 240)
Thecospira sp.
Triassic (St Cassian beds), Alpe de Specie (formerly Seelandalpe), 2-5 km NW of
Carbonin (formerly Schluderbach), n km NE of Cortina d'Ampezzo, Trentino, Italy
FIG. 3. Section through a brachial valve showing primary and secondary shell layers.
BB 59007. x 1400. (p. 241)
FIG. 4. Section through the secondary layer showing the characteristic shape and stacking
of fibres. Same specimen, BB 59007. x 2800. (p. 242)
FIG. 5. Section through the cementation area of a pedicle valve. A narrow zone, mainly
infilled with sediment, separates the secondary layer fibres of Thecospira (top) from the prismatic
layers of a molluscan shell fragment (bottom) to which the brachiopod is attached. Same speci-
men as PI. 31, figs. 3, 5-6, BB 59005. X7oo. (p. 241) (See also Text-fig. 19.)
Bull. BY. Mus. nat. Hist. (Geol.) 25, 3
PLATE 26
PLATE 27
All figures are scanning electron micrographs of the shell.
Thecospira sp.
Triassic (St Cassian beds), Alpe de Specie (formerly Seelandalpe), 2-5 km NW of
Carbonin (formerly Schluderbach), u km NE of Cortina d'Ampezzo, Trentino, Italy.
Same specimen as PI. 28, figs. 1-2, BB 59008
FIG. i . Oblique section of a tubercle core within the secondary layer showing the deflection
of fibres. x 1400. (p. 242)
FIG. 2. Section through a tubercle submerged within the secondary layer showing the inward
deflection of fibres. x 670. (p. 242)
FIG. 3. Section through a submerged tubercle showing some transverse depositional banding
and the inward deflection of secondary layer fibres. x 1350. (p. 242)
FIG. 4. More general view of fig. 3, showing primary (top right) and secondary layers.
Tubercle cores can be recognized within the secondary layer which is also penetrated by puncta.
X270. (pp. 242, 243)
FIG. 5. Section through the secondary layer showing the outward deflection of fibres around
a punctum. Several transverse micritic bands are also outwardly deflected around the punctum.
X650. (p. 243)
FIG. 6. More detailed view of a section through the secondary layer showing a porous,
micritic band. x 2650. (p. 243)
Bull. BY. Mus. nat. Hist. (Geol.) 25, 3
PLATE 27
PLATE 28
All figures are scanning electron micrographs of the shell (figs, i, 2) or spiralium (figs. 3-6).
Thecospira sp.
Triassic (St Cassian beds), Alpe de Specie (formerly Seelandalpe) , 2-5 km NW of
Carbonin (formerly Schluderbach), n km NE of Cortina d'Ampezzo, Trentino, Italy.
Same specimen as PL 27, BB 59008
FIG. i. Section through a brachial valve showing part of a dorsal adductor myotest. x 1250.
(P- 243)
FIG. 2. General view of a section through the overhanging ridge located at the anterior
margin of the ventral diductor muscle scar, x 140. (p. 243)
Protozyga elongata Cooper
FIG. 3. Ordovician (Lower Bromide Formation), i mile west of Dolese Brothers Crusher,
Bromide, Oklahoma. Transverse section through one prong of the rudimentary spiralium.
Same specimen as PL 6, fig. 5, BB 58918. x 2800. (p. 244)
Catazyga headi (Billings)
FIG. 4. Ordovician (Richmond Group), Adana Co., near Winchester, Ohio. Transverse
section through a spiral lamella showing the double-sided distribution of secondary layer fibres.
Same specimen as PL 7, figs. 1-3, BB 58921. x 1350. (p. 245)
Idiospira thotnsoni (Davidson)
Ordovician (Craighead Limestone), Girvan, Ayrshire.
Same specimen as PL 7, figs. 4-5, BB 58922
FIG. 5. Transverse section through a spiral lamella showing the double-sided distribution of
secondary layer fibres, x 610. (p. 245)
FIG. 6. More detailed view of part of fig. 5, showing the deflection of fibres around a spine
base which projects from the median-facing side of the lamella. x 2400. (p. 245)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 28
PLATE 29
All figures are scanning electron micrographs of the spiralium.
Dayia navicula (Sowerby)
FIG. i. Ludlovian (Dayia Shales), Park Farm Quarry, Onibury, Shropshire. Transverse
section through a spiral lamella showing the double-sided distribution of secondary layer fibres.
BB 58934. x 1200. (p. 245) (See also PI. 9, figs. 5-6.)
Rhynchospirina maxwelli Amsden
FIG. 2. Devonian (Haragan Formation), White Mound, Murray County, Oklahoma. Trans-
verse section through a spiral lamella showing the double-sided distribution of secondary layer
fibres. Same specimen as PI. 10, fig. 3, BB 58936. x 700. (p. 245)
Ambocoelia utnbonata (Conrad)
FIGS. 3, 4. Devonian (Wanakah Shale), Canandaiga Lake, New York State. Transverse
section through a spiral lamella showing the double-sided distribution of secondary layer fibres.
Same specimen as PI. 17, figs. 2, 3, BB 58971. x 600, x 2600. (p. 245)
Theodossia hungerfordi (Hall)
FIG. 5. Devonian (Hackberry Stage), Tile Yard, Rockford, Iowa. Transverse section
through a spiral lamella showing the double-sided distribution of secondary layer fibres. Same
specimen as PL 21, figs. 1-2, BB 58986. x 630. (p. 245)
Spirifer trigonalis Martin
FIG. 6. Carboniferous (Douglas Main Limestone), Lower Limestone Group, Brockley, Lanark-
shire. Transverse section through a spiral lamella showing the double-sided distribution of
secondary layer fibres. Same specimen as PI. 22, figs. 3, 5, BB 58992. x 650. (p. 245)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 29
s
^si^SS^g
^:<vr>5^*^-*^SSV ';- •"- ',% .JXtj v pi
^^^iSS^ J
K-^-S ^ J- V;v :- r'^Xv^^ I
^>->X^'ii''?''%''?7i^ !
^^S^'^TN^^^ "*• :
X.11**.^ ' v.41*:^'^ **. W» ^ ffc« ii •
SSL^-?! -ss^»5r:i'.^_if|;*|'^Sjfip»drs
PLATE 30
All figures are scanning electron micrographs of the spiralium.
Composita ambigua (Sowerby)
Carboniferous (Calmy Limestone), Carluke, Lanarkshire.
BB 58950. (See also PL 13, fig. i)
FIG. i. Section through a spiral lamella showing the flat apical-facing side (bottom left
corner). Growth is one-sided. X 280. (p. 247)
FIG. 2. More detailed view of part of fig. i, showing the regular shape and stacking of fibres.
X28oo. (p. 247)
Athyris spiriferoides (Eaton)
FIG. 3. Devonian (Wanakah Shale), Canandaiga Lake, New York State. Transverse
section through a spiral lamella showing the disposition of fibres. The curved keels are convex
towards the median-facing side (bottom) . 6658949. xiiso. (p. 247) (See also PI. 12, figs.
5-6.)
Diplospirella wisstnani (Miinster)
FIG. 4. Triassic (St Cassian beds), Alpe de Specie (formerly Seelandalpe), 2-5 km NW of
Carbonin (formerly Schluderbach), n km NE of Cortina d'Ampezzo, Trentino, Italy. Section
through a primary lamella showing the disposition of secondary layer fibres. Growth is one-
sided. Same specimen as PL 13, fig. 5, BB 58956. x 1300. (p. 247)
Anisactinella quadriplecta (Miinster)
FIG. 5. Triassic (St Cassian beds), i km E of Rif. Pralongia-Htt. (Pralongia Refuge Chalet),
Pralongia Ridge, 4-5 km ESE of Corvara in Badia, Italy. Transverse section through a primary
lamella showing the disposition of secondary layer fibres. A spine base (right) projects from the
median-facing side. Same specimen as PL 15, fig. 2, BB 58960. x 2500. (p. 247)
Koninckina leonhardi (Wissman)
FIG. 6. Triassic (St Cassian beds), 0-5 km SE of Rif. Pralongia-Htt. (Pralongia Refuge
Chalet), 4 km SE of Corvara in Badia, Italy. Transverse section through a primary lamella
showing the shape and stacking of constituent secondary layer fibres. Same specimen as PL 16,
figs, i, 6 and PL 31, fig. i, BB 58961. x 1400. (pp. 247, 250)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 30
PLATE 31
All figures are scanning electron micrographs of the spiralium.
Koninckina leonhardi (Wissman)
FIG. i. Triassic (St Cassian beds), 0-5 km SE of Rif. Pralongia-Htt. (Pralongia Refuge
Chalet), 4 km SE of Corvara in Badia, Italy. Transverse section through a primary (top) and
accessory (bottom) lamella seen in attitudes of growth relative to one another. Same specimen
as PI. 16, figs, i, 6, and PI. 30, fig. 6, BB 58961. x6jo. (pp. 247, 250)
Amphiclina amoena Bittner
Triassic (St Cassian beds), Alpe de Specie (formerly Seelandalpe), 2-5 km NW of
Carbonin (formerly Schluderbach), n km NE of Cortina d'Ampezzo, Trentino, Italy.
BB 58968. (See also PL 15, fig. 6 and PI. 16, fig. 3)
FIG. 2. View of the resorbed face of a primary lamella showing the trails of fibres disposed
obliquely across its surface. x 130. (pp. 247, 250)
FIG. 4. More detailed view of part of fig. 2, showing the series of narrow troughs and ridges
aligned at right angles to the outer edge of the primary lamella. x 1200. (p. 250)
Thecospira sp.
Triassic (St Cassian beds), Alpe de Specie (formerly Seelandalpe), 2-5 km NW of
Carbonin (formerly Schluderbach), n km NE of Cortina d'Ampezzo, Trentino, Italy.
Same specimen as PL 26, fig. 5, BB 59005
FIG. 3. Transverse section through part of the dorsal limb of a spiral lamella showing the
stacking of secondary layer fibres. x 670. (p. 247)
FIG. 5. Transverse section through part of the ventral non-fibrous limb of a U-shaped spiral
lamella showing a series of concentric bands which are probably depositional. x 2800. (p. 251)
FIG. 6. Transverse section through part of the dorsal limb of a U-shaped spiral lamella
showing non-fibrous, concentrically banded zones. x 1350. (p. 251)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 31
PLATE 32
Thecospira sp.
Scanning electron micrograph montage of the spiralium of a specimen from the Triassic (St
Cassian beds), Alpe de Specie (formerly Seelandalpe), 2-5 km NW of Carbonin (formerly Schluder-
bach), ii km NE of Corvara d'Ampezzo, Trentino, Italy. Transverse section through a spiral
lamella showing the general U-shaped profile. Longer, dorsal limb to left, shorter ventral limb
to right. BB 59006. x 300. (p. 251)
Bull. Br. Mus. nat. Hist. (Geol.) 25, 3
PLATE 32
A LIST OF SUPPLEMENTS
TO THE GEOLOGICAL SERIES
OF THE BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
1. Cox, L. R. Jurassic Bivalvia and Gastropoda from Tanganyika and Kenya.
Pp. 213 ; 30 Plates ; 2 Text-figures. 1965. £6.
2. EL-NAGGAR, Z. R. Stratigraphy and Planktonic Foraminifera of the Upper
Cretaceous — Lower Tertiary Succession in the Esna-Idfu Region, Nile Valley,
Egypt, U.A.R. Pp. 291 ; 23 Plates ; 18 Text-figures. 1966. £10.
3. DAVEY, R. J., DOWNIE, C., SARGEANT, W. A. S. & WILLIAMS, G. L. Studies on
Mesozoic and Cainozoic Dinoflagellate Cysts. Pp. 248 ; 28 Plates ; 64 Text-
figures. 1966. £7.
3. APPENDIX. DAVEY, R. J., DOWNIE, C., SARGEANT, W. A. S. & WILLIAMS, G. L.
Appendix to Studies on Mesozoic and Cainozoic Dinoflagellate Cysts. Pp. 24.
1969. Sop.
4. ELLIOTT, G. F. Permian to Palaeocene Calcareous Algae (Dasycladaceae) of the
Middle East. Pp. in ; 24 Plates ; 17 Text-figures. 1968. £5.i2f.
5. RHODES, F. H. T., AUSTIN, R. L. & DRUCE, E. C. British Avonian (Carboni-
ferous) Conodont faunas, and their value in local and continental correlation.
Pp- 3*5 ; 31 Plates ; 92 Text-figures. 1969. £11.
6. CHILDS, A. Upper Jurassic Rhynchonellid Brachiopods from Northwestern
Europe. Pp. 119 ; 12 Plates ; 40 Text-figures. 1969. £4.75.
7. GOODY, P. C. The relationships of certain Upper Cretaceous Teleosts with
special reference to the Myctophoids. Pp. 255 ; 102 Text-figures. 1969.
£6.50.
8. OWEN, H. G. Middle Albian Stratigraphy in the Anglo-Paris Basin. Pp. 164 ;
3 Plates ; 52 Text-figures. 1971. £6.
9. SIDDIQUI, Q. A. Early Tertiary Ostracoda of the family Trachyleberididae
from West Pakistan. Pp. 98 ; 42 Plates ; 7 Text-figures. 1971. £8.
10. FOREY, P. L. A revision of the elopiform fishes, fossil and recent. Pp. 222 ;
92 Text-figures. 1973. £9.45.
11. WILLIAMS, A. Ordovician Brachiopoda from the Shelve District, Shropshire.
28 Plates. In press, expected 1974.
Printed in Great Britain by John Wright and Sons Ltd. at The Stonebridgc Preu, Bristol BS4 5NU
CRETACEOUS FAUNAS FROM
ZULULAND AND NATAL,
SOUTH AFRICA
INTRODUCTION, STRATIGRAPHY
W. J. KENNEDY
AND
H. C. KLINGER
BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
GEOLOGY Vol. 25 No. 4
LONDON: 1975
9 GENERAL
28 JAM975
CRETACEOUS FAUNAS FROM ZULULANDWIBRARY^>
AND NATAL, SOUTH AFRICA
INTRODUCTION, STRATIGRAPHY
BY
WILLIAM JAMES KENNEDY
AND
HERBERT CHRISTIAN KLINGER
Pp. 263-315 ; i Plate ; 12 Text-figures
BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
GEOLOGY Vol. 25 No. 4
LONDON: 1975
THE BULLETIN OF THE BRITISH MUSEUM
(NATURAL HISTORY), instituted in 1949, is
issued in five series corresponding to the Departments
of the Museum, and an Historical series.
Parts will appear at irregular intervals as they
become ready. Volumes will contain about three or
four hundred pages, and will not necessarily be
completed within one calendar year.
In 1965 a separate supplementary series of longer
papers was instituted, numbered serially for each
Department.
This paper is Vol. 25, No. 4 of the Geological
(Palaeontological) series. The abbreviated titles of
periodicals cited follow those of the World List of
Scientific Periodicals.
World List abbreviation :
Bull. Br. Mus. nat. Hist. (Geol.)
Trustees of the British Museum (Natural History), 1975
TRUSTEES OF
THE BRITISH MUSEUM (NATURAL HISTORY)
Issued 3 January 1975 Price £3.75
CRETACEOUS FAUNAS FROM ZULULAND
AND NATAL, SOUTH AFRICA
INTRODUCTION, STRATIGRAPHY
By WILLIAM J. KENNEDY AND HERBERT C. KLINGER
CONTENTS
Page
I. INTRODUCTION ......... 266
II. PLACE NAMES .......... 267
III. STRATIGRAPHIC SYNTHESIS ....... 267
IV. HISTORY OF RESEARCH ........ 269
V. STRATIGRAPHIC NOMENCLATURE. ...... 272
VI. STAGE LIMITS AND SUBDIVISIONS ...... 273
BARREMIAN ......... 273
APTIAN .......... 274
ALBIAN .......... 275
CENOMANIAN ......... 276
TURONIAN .......... 277
CONIACIAN .......... 278
SANTONIAN .......... 279
CAMPANIAN .......... 280
MAASTRICHTIAN . . . . . . . . .281
VII. LOCALITY DETAILS ......... 281
A. PONDOLAND ......... 281
B. DURBAN ......... 282
C. KWA-MBONAMBI, ZULULAND ...... 282
D. MFOLOZI AND UMKWELANE HILL, ZULULAND . . . 282
E. THE NYALAZI RIVER, SOUTH OF HLUHLUWE, ZULULAND . 283
F. GLENPARK ESTATE, ZULULAND ..... 284
G. THE MZINENE RIVER AND ITS TRIBUTARIES, ZULULAND . 285
(i) Upper reaches ....... 285
(ii) The Skoenberg region . . . . . 288
(iii) Sections along the Munywana .... 289
(iv) Lower reaches ....... 292
H. SECTIONS AROUND FALSE BAY AND LAKE ST LUCIA,
ZULULAND. ........ 292
(i) Western False Bay ...... 292
(ii) The Hluhluwe flood plain ..... 294
(a) Western side ...... 294
(b) Eastern side ...... 295
(iii) False Bay : SE shores ..... 295
(iv) The Nibela Peninsula ...... 296
(v) The Southern Peninsula ..... 296
(vi) Lake St Lucia ....... 298
J. THE MKUZE RIVER AND ITS TRIBUTARIES .... 298
(i) Southern part of Mkuze Game Reserve . . . 299
(ii) The Morrisvale Area ...... 299
(iii) Mantuma Rest Camp Area ..... 300
266 CRETACEOUS FAUNAS
K. NORTHERN ZULULAND . . . . . . . 300
(i) Mayezela Spruit. . . . . . . 301
(ii) Mfongosi Spruit ....... 301
(iii) Mlambongwenya Spruit ..... 302
(iv) Ndumu ........ 302
VIII. DISCUSSION .......... 304
IX. ACKNOWLEDGEMENTS ........ 306
X. REFERENCES .......... 306
XI. INDEX . . . . . . . . . . . 312
SYNOPSIS
Cretaceous sediments outcrop in two main areas in eastern South Africa, north of Durban,
from the Mfolozi River to the Mozambique border, and to the south, between the Itongazi and
Mpenjati Rivers.
The term Zululand Group is proposed for the succession in the northern area, subdivided into :
(i) The Makatini Formation (Upper Barremian to Aptian) ; (2) The Mzinene Formation
(Albian to Cenomanian) ; (3) The St Lucia Formation (Coniacian to Maastrichtian) . The term
'Umzamba Formation' is retained for the Coniacian to Campanian sequences south of Durban.
Sedimentation began in Lower Cretaceous (pre-Upper Barremian) times, with deposition of
piedmont fan and fluviatile sands and conglomerates in northern Zululand. Transgression,
beginning during the Upper Barremian, extended through at least into Albian, and probably
Cenomanian, times, depositing first sands and conglomerates, followed by glauconitic silts.
During late Cenomanian or early Turonian times, regression was under way, accompanied by
widespread penecontemporaneous erosion. The highest Cenomanian and all the Turonian are
thus absent on land. Renewed transgression during the early Coniacian extended through into
at least the Campanian, and the base of the Senonian is diachronous. In northern Zululand,
Coniacian silts rest on lithologically similar Upper Cenomanian deposits. Along the Mfolozi
River, slightly higher horizons in the Coniacian rest first on Lower Cretaceous conglomerates
and, to the south, overstep onto Stormberg Basalts and Basement rocks. South of Durban,
yet higher horizons in the Coniacian rest on formations down to the Table Mountain Sandstone.
Preliminary work on the ammonite faunas allows subdivision of the Barremian to Lower
Maastrichtian stages into 31 widely recognizable units and points to the development of a refined
biostratigraphy when systematic work is complete. Apart from ammonites, the Cretaceous
sequences described yield a rich fauna. Bivalves, gastropods and nautiloids are abundant,
with scarcer echinoids, brachiopods, bryozoans and corals. Locality details of 185 sections in
the area are given as a basis for subsequent taxonomic work.
I. INTRODUCTION
DURING the summers of 1970-71 we collected from and measured the sections at
over 150 localities in the Cretaceous successions of Zululand, Natal, and the Northern
Transkei. Many of the fossils collected have been added to the collections of the
British Museum (Natural History), which already contain classic South African
material described by Daniel Sharpe, G. C. Crick, R. B. Newton, R. Etheridge, L. F.
Spath and others, examined by us.
In addition, we have studied important collections in the Geological Survey of
South Africa at Pretoria, including material collected by one of us (H. C. K.), by
E. C. N. van Hoepen, S. H. Haughton and others. We have also been able to study
ZULULAND AND NATAL 267
the collections of the Transvaal Museum, the National Museum Bloemfontein, the
South African Museum, Cape Town, the Durban Museum, and the University
Collections at Durban and Pretoria.
The present publication is the first of a series in which we intend to describe the
invertebrate faunas collected in this region. This work will need many years of
study, for the South African Cretaceous yields diverse faunas which, in spite of an
extensive literature (Haughton, 1959, provides the most complete bibliography),
remain largely unknown in contemporary terms, whilst an acceptable stratigraphic
framework is still lacking. Detailed biostratigraphy must await the results of further
research, as must palaeoecological and palaeoenvironmental syntheses ; we present
here an outline of the geological history of the area, a provisional biostratigraphy
upon which to base our systematic work, and locality information of relevant
sections.
II. PLACE NAMES
Over most of the area described in this paper, place names are taken from the
Second Edition of the i : 50 ooo and the i : 250 ooo topographic maps of South
Africa. Standardization of spelling of Zulu names leads to the alteration of the
names of many classic localities. Thus the Umsinene becomes the Mzinene, Manuan
becomes Munywana, and so on.
III. STRATIGRAPHIC SYNTHESIS
Cretaceous sediments outcrop in two main areas in eastern South Africa (Fig. i) ;
in Zululand, from the Mozambique border south to Umkwelane Hill on the Mfolozi
River, and south of Durban, as reefs exposed only at low tide as between the Itongazi
and Mpenjati Rivers, or in low cliffs, as at the mouth of the Umzamba River. There
are small but important outcrops at Enseleni Reserve, and subsurface Cretaceous is
recorded at Durban and Richards Bay.
Exposures are poor in the region studied, whilst dips are low and difficult to
measure. The probable thickness of the Cretaceous in the St Lucia area is of the
order of 1000 m, but the sequence quite clearly thickens northwards and eastwards,
suggesting the presence of a substantial wedge of sediment out to sea.
In northern Zululand, coarse clastic pre-Upper Barremian fluviatile Cretaceous
sediments rest on Jurassic Lebombo Volcanics. The lowest marine horizons known
consist of Upper Barremian silts, sandstones and conglomerates. The succeeding
Aptian has a similar facies, and in the area around Hluhluwe, this too rests on the
Lebombos. The Albian/ Aptian boundary is an important non-sequence marked by
a horizon of hiatus concretions (Kennedy & Klinger 1972) which can be traced for
175 km, from Ndumu to 12 km north of Mtubatuba. Lowermost Albian sediments
seem to be wholly absent in Zululand. Locally, the Albian may overlap onto
Lebombo Volcanics. In general, however, the Albian forms an expanded sequence
of shallow marine silts and sands, sometimes glauconitic, with shelly concretionary
268
CRETACEOUS FAUNAS
PORT SHEPSTONE
UMZAMBA
FIG. i. Locations of the areas studied.
horizons and small-scale sedimentary cycles. Locally a more marginal basal conglo-
meratic facies may be developed. Horizons up to and including the Stoliczkaia
dispar Zone have been recognized, followed by a conformable Lower, Middle and
Upper Cenomanian sequence, again in a silty glauconitic facies, and with a rich
marine fauna.
Turonian rocks are absent on land in Zululand, and along the Mzinene River a
Coniacian basal conglomerate rests on Cenomanian silts, with a horizon of hiatus
concretions at the contact (Kennedy & Klinger 1972). Along the Mzinene,
Hluhluwe and Nyalazi Rivers, around False Bay and Lake St Lucia, a succession
from Coniacian through to Lower Maastrichtian can be traced ; the sequence is,
throughout, one of shelly, sometimes glauconitic, silts, with concretionary horizons.
The next extensive outcrops of Cretaceous sediments appear along the Mfolozi
River and at Umkwelane Hill (Fig. i). At Riverview, Lower Coniacian sediments
rest on Lower Cretaceous non-marine fluviatile conglomerates, and to the south, at
ZULULAND AND NATAL 269
Umkwelane Hill, overstep onto Stormberg Basalts and granitic basement rocks
within a distance of only a few kilometres. The basal Coniacian is a thin con-
glomerate ; fossils from just above the base of the sequence at Umkwelane Hill
suggest a horizon higher than that seen in the basal Coniacian along the Mzinene.
Above, there is a succession of silts and shelly limestones extending up to the Lower
Campanian. Probable Upper Campanian silts occur to the east, and around Monzi
horizons up to the Lower Maastrichtian are present.
Cretaceous silts and shell beds are known beneath Durban, and sparse faunas
indicate the presence of horizons in the Campanian and high in the Santonian.
South of Durban, the deposits of the Upper Cretaceous transgression rest on horizons
down to the Table Mountain Sandstone. The age of these, the Umzamba Beds, has
long been disputed (p. 270), but a high Coniacian (?) to Campanian age seems most
likely.
Available evidence thus indicates that sedimentation began in Lower Cretaceous
(pre-Upper Barremian) times, with deposition of piedmont fan and fluviatile sands
and conglomerates. Transgression, beginning during the Upper Barremian, ex-
tended through at least into Albian, and probably Cenomanian, times, but during
late Cenomanian or early Turonian times regression was under way, accompanied by
widespread penecontemporaneous erosion. Renewed transgression during the early
Coniacian extended through into the Campanian at least, and the base of the
Senonian is diachronous from Zululand, 600 km to the south, into the Northern
Transkei.
IV. HISTORY OF RESEARCH
The Cretaceous rocks of eastern South Africa were first discovered by H. F. Fynn
in 1824, although they were not described until three decades later. Thus Captain
R. J. Garden (1855 : 453-454) gave as graphic and accurate a picture of the Um-
zamba Beds as any during the following century :
'. . . the lowest rock visible is a hard shelly rock with pebbles ; above it is a brownish-red
sandstone, traversed in every direction by white veins, which are the broken edges of colossal
bivalve shells (Inoceramus). The shells are thin, and too easily broken to be extracted from
the rock . . . alternate layers of the above mentioned two rocks occur to the height of about
eighteen feet, above which are hard bluish-black, brown and greenish argillaceous and sandy
beds. Shells were found in all these clay beds, and Ammonites at different heights, and in
certain of the strata . . . Fossil trees are seen at low water on a reef of flat rocks (nearby).'
The fossils collected by Garden were described by W. H. Bailey in the succeeding
pages of the Quarterly Journal of the Geological Society of London.
This section passed into the literature as the Umtamvuna or Umtamfuna Creta-
ceous (Tate 1867, Griesbach 1871, Gottsche 1887, Etheridge 1904, Crick 1907^
J-907d, and others), on the basis of the misconception that they outcrop at the mouth
of the Umtamvuna River, although Griesbach (1871) refers to them as the Izin-
dhluzabalungu Deposits. Latterly, they have become known as the Umzamba Beds,
and in addition to the type section, outcrops have been described at several localities
270 CRETACEOUS FAUNAS
along the coast of southern Natal (Pondoland), in particular between the Itongazi
and Umkandandhlouvu Rivers (Griesbach 1871, Rogers & Schwartz 1901, 1902,
Crick I907b, Plows 1921, Gevers & Little 1956, du Toit 1920, 1954, Haughton
1969). The most satisfactory description of the type section is that of Plows (1921).
Faunas and floras have been described by Griesbach (1871), Chapman (1904, 1923),
Lang (1906), Woods (1906), Rennie (1930, 1935), Spath (192 ib, I922a), van Hoepen
(1920, 1921, I966a), Broom (1907), Crick (igoyb), Little (1957), Smitter (1956),
Mandel (1960), Muller-Stoll & Mandel (1962), and Dingle (1969).
The age suggested for the Umzamba Beds has varied from Albian or Cenomanian
to Maastrichtian, and the view long accepted that but a single faunal horizon is
represented (Woods 1906, Rennie 1930, du Toit 1954). The most recent appraisal
of the ammonites by Spath (1953) led him to suggest a Campanian to Lower Maas-
trichtian age for the fauna, and the latest microfaunal study led Dingle (1969) to a
similar conclusion.
In fact, the base of the Umzamba Beds in the type section has yielded a Coniacian
collignoniceratid : Subprionotropis cricki (Spath) ( = Barroisiceras umzambiensis
van Hoepen), whilst inoceramids and ammonites from higher in the section are of
Santonian/Campanian age. There is no evidence for the Lower Maastrichtian. The
outcrops between the Itongazi and Mpenjati Rivers yield Santonian inoceramids
and ammonites.
The presence of Cretaceous rocks beneath Durban was first noted by Anderson
(1906 : 48), whilst faunas have been recorded by Krige (1932) and King & Maud
(1964), all of whom equate the sequence with the Umzamba Beds. Material from
recent excavations indicate the presence of horizons within both the Santonian and
the Campanian stages.
North of Durban, Cretaceous sediments in the Lake St Lucia region were first
recorded by Griesbach (1871). The principal work in this area was, however, by
William Anderson, the one-man Geological Survey of Zululand and Natal. Anderson
noted possible subsurface Cretaceous occurrences in the region of what he called the
Umlatuzi Lagoon, and described important sections in two areas : along the Mfolozi
River and Umkwelane Hill, and along the Mzinene River and its tributaries. He also
noted the occurrence of Cretaceous deposits as far north as the junction of the Ing-
wavuma and Pongola Rivers (1907 : 60-61), whilst Kilian had recorded Aptian sedi-
ments across the border in southern Mozambique a few years previously (Kilian
i9O2a-c ; see also Krenkel igioa-c, igiia-b).
Faunas from Umkwelane Hill were described by Etheridge (1904), who compared
them with those of the Umzamba Beds of Pondoland (see also Woods 1906 : 337) and
the Arialoor and Trichinopoly Groups of Southern India (then regarded as Turonian
and Senonian respectively). Crick (i9O7a : 228) recorded a further ammonite,
Mortoniceras umkwelanense Crick, and confirmed an Upper Cretaceous age for the
deposits ; additional fossils were recorded by R. B. Newton in 1909. No further
work was published until Spath (i92ia) described a large collection of ammonites
made by A. L. du Toit from exposures at and near Umkwelane Hill. On the basis
of this material Spath identified the Campanian and Maastrichtian stages as being
present in the area. This region was visited during excursion Ci8 of the 1929
ZULULAND AND NATAL 271
International Geological Congress (du Toit & van Hoepen 1929), and a series of
papers describing and discussing the region resulted (Heinz 1930, Besaire 1930,
Venzo 1936, Dietrich 1938, Socin 1939, Montanaro & Lang 1937).
Heinz, Besaire and van Hoepen all claimed to recognize Turonian rocks at the
base of the sequence, followed by horizons from Coniacian through to Campanian.
Rennie (1930) returned to the view that the sequence was equivalent to the Umzamba
Beds, accounting for peculiarities in ammonite fauna on the basis of facies differences.
Du Toit (1954) suggested a Lower Santonian age for the sequence, whilst Frankel
suggested Coniacian to Upper Santonian or Campanian. Our own collecting in-
dicates that horizons from Lower Coniacian to well up into the Campanian are
represented, and that Upper Campanian and Maastrichtian sediments are present
to the east, beneath the Tertiary and Recent deposits around Monzi.
Early work on the Lake St Lucia and Mzinene region centre around collections
made by Anderson (1902-07) and their description by Etheridge (1907) and Crick
(i907a, c). Etheridge gave no date to the material he described (although it is
undoubtedly an Albian assemblage) , but Crick recognized a Cenomanian fauna from
the 'north end of False Bay' (later corrected to the junction of the Munywana and
Mzinene Rivers), and recorded Upper Albian and Senonian fossils from the Muny-
wana. Spath (192 1 a) added further records and in addition recognized supposed
Coniacian and Campanian forms.
Van Hoepen (1926-66) described a vast number of ammonite species from this
part of Zululand, suggested a classification of the succession, and recognized Aptian
to Maastrichtian stages, as discussed below (p. 272) . His basic views were supported
in publications resulting from the 1929 Congress visit (Besaire 1930, Besaire &
Lambert 1930, Heinz 1930, Venzo 1936, Socin 1939, Montanaro & Lang 1939).
Van Hoepen's systematic work (1929 onwards) suffers from extensive splitting, and
the majority of his taxa are synonyms of well-established classic genera and species
(see, for instance, Haas 1942, Wright 1957).
Since van Hoepen's work, little has been published. Muir-Wood (1953) described
a single brachiopod from the Mzinene whilst Foraminiferida are noted by Smitter
(1957). As already described (Kennedy & Klinger 1971 ; see also p. 268 above),
the section in this area is in fact incomplete, and the supposed Maastrichtian of van
Hoepen and others is high Campanian.
North of the Mzinene, supposed Turonian sediments were described by van
Hoepen in du Toit & van Hoepen (1929) from close to the junction of the Mkuze
and Msunduzi Rivers, and apparently accepted as such by many other workers (e.g.
Besaire 1930, Venzo 1936, Furon 1950, 1963). These beds, said to be characterized
by large oysters, are of a Coniacian age, the oysters coming from the overlying
Tertiary. Still further north, there are excellent accounts of sections along streams
draining east from the Lebombos to the Pongola River by Haughton (i93&a) and
Boshoff (1945), and some molluscs from the area were described by Rennie (1936).
Unfortunately, the rich ammonite faunas (Haughton I936b, Spath 1953) were never
described, although horizons from Upper Aptian to Upper Albian were recognized.
Some additional information is provided by Spath (1925), Dietrich (1938), and
Haughton (1969).
272
CRETACEOUS FAUNAS
No horizons higher than the Lower Cenomanian are exposed at the surface in this
northernmost part of Zululand, for east of the Pongola the country is a wilderness of
drifted sand. Davey (1969) and Pienaar (1969) have, however, described Campanian
to Palaeocene micron1 oras from a deep borehole in the Lake Sibayi region.
V. STRATIGRAPHIC NOMENCLATURE
Present nomenclature of the Cretaceous deposits of Zululand and Natal is in a far
from satisfactory state. The term 'Umzamba Beds' is used for the Santonian and
Campanian strata of Southern Natal, whilst to the north, the following terms have
been used in the Mzinene-St Lucia region by van Hoepen (1926, 1929) and others :
Umzamba Beds
Itweba Beds
Peroniceras Beds
Munyuana Beds
Skoenberg Beds
Umsinene Beds
Ndabana Beds
Upper Senonian
Middle Senonian
Lower Senonian
Turonian
Cenomanian
Albian
Aptian/Albian
These divisons are variously described as 'Beds' or 'Zones' and it is quite clear from
van Hoepen's original accounts (1926, 1929) that they are based upon faunal dif-
ferences, and that, apart from the conglomerate and sandstone units of the Ndabana
Beds and the sandy base of the Umsinene Beds, the sequence is of a uniform silt
facies.
These divisions are thus neither wholly lithostratigraphic nor biostratigraphic
units, nor are they precisely defined in terms of faunas or lithology. We see no need
for a local biostratigraphic system, for the internationally recognized stages of the
Cretaceous can be recognized in South Africa. We therefore propose the lithostrati-
graphic terminology outlined in Table i.
TABLE i
Lithostratigraphic and biostratigraphic subdivisions of the Zululand Cretaceous
KENNEDY & KLINGER (herein) STAGES
C Lower Maastrichtian
J Campanian
I Santonian
I^Coniacian
f Cenomanian
VAN HOEPEN (1926, 1929)
Umzamba Beds
Itweba Beds
Peroniceras Beds
Munyuana Beds
Skoenberg Beds
Umsinene Beds
Zululand
Group
Ndabana Beds
j
St Lucia Formation
Mzinene Formation
Makatini Formation
^_ Albian
fAptian
\^ Upper Barremian
(pre-Upper Barremian ?)
ZULULAND AND NATAL 273
We further propose that the Cretaceous sediments developed in Zululand be termed
the Zululand Group, and that the term 'Umzamba Formation' be retained for the
Upper Cretaceous deposits of Pondoland.
Definitions of these lithostratigraphic units are as follows :
Zululand Group
1. The Makatini Formation. The type section extends along the Mfongosi
Spruit, in northern Zululand, from where the base of the formation rests on Lebombo
Volcanics to Loc. 169, 27° 21' 38" S, 32° 09' 57" E. The succession consists of sand-
stones, siltstones and conglomerates, with marine Upper Aptian fossils. Details of
localities are given on pp. 301-302. To the north, along the Mlambongwenja, the
same formation yields Upper Barremian and Aptian marine faunas.
2. The Mzinene Formation. The type section extends along the Mzinene River
from Loc. 51, 27° 53' 43" S, 32° 19' 22" E, to Loc. 60, 27° 52' 45" S, 32° 20' 55" E.
The base of the formation is taken at the minor non-sequence and bored concretion
bed which separates the Aptian and Albian stages. A complete succession up to
and including the lower part of the Upper Cenomanian is represented in this forma-
tion, which consists largely of silts with shelly and concretionary horizons. Details
of localities are given on p. 288.
3. The St Lucia Formation has as its type locality river bank sections along the
Mzinene from Loc. 60, 27° 52' 45" S, 32° 20' 55" E, to its entry into False Bay, and
the cliff and foreshore sections around False Bay and Lake St Lucia. The base of
the formation is taken at the base of the Coniacian conglomerate exposed at Loc. 60
on the Mzinene (p. 288) : locality details are given on pp. 288-298. The succession
consists predominantly of siltstones, with concretionary and shelly horizons. The
base of the formation is of Lower Coniacian age ; the highest horizons exposed at the
surface yield Lower Maastrichtian ammonites and inoceramid bivalves.
The Umzamba Formation has as its type section the cliffs and foreshore exposures
north of the mouth of the Umzamba River, 31° 06' S, 30° 10' E approximately.
The type section ranges in age from high Coniacian to Campanian.
VI. STAGE LIMITS AND SUBDIVISIONS
All the stages of the Cretaceous present problems of definition, and almost without
exception international usage is highly variable. For clarity, we outline here our
working definitions of the Barremian to Maastrichtian stages. Since correlation
with the European type areas is still not fully possible, and because the European
stratotypes still present problems of interpretation, these are 'local' definitions only.
We also present our working subdivisions of the stages, although again it must be
stressed that all our systematic determinations are provisional. A far more detailed
biostratigraphic system will be available when our taxonomic work is complete.
BARREMIAN
'L'etage Barremien' was introduced by Coquand in 1862. The type area for the
stage is the environs of Barreme, near Digne, Basses-Alpes, France. Busnardo
274 CRETACEOUS FAUNAS
has designated the Angles section close by as stratotype : recent discussions
of the stage in its type area are given by Sornay (1957), Busnardo (ig65a, b), Guillame
& Sigal (1965), Bouche (1965) and Faure (1965) ; an English summary is given by
Middlemiss & Moullade (1970 : 352-354).
We have recognized only Upper Barremian faunas in Zululand, so that the vexing
problem of the base of the stage and the position of the Pseudothurmannia anguli-
costata Zone is not relevant here. The Mesogean aspect of much of the fauna of the
type Barremian makes direct correlation with our sequence difficult. More relevant
is the work of Druzhchitz (i963a, b) on the revision of the Barremian sequence in
Georgia, Dagestan and the Northern Caucasus, which clearly demonstrates the upper-
most Barremian age of the classic 'Aptian' Colchidites faunas of the region described
by Rouchadze (1932), Eristavi (1955), Rengarten (1926) and others. These faunas
closely resemble our Zululand material and are the basis for recognition of the
Upper Barremian.
Barremian I
Characterized by an abundance of crioceratitids, including a variety of 'Emerici-
ceras' and 'Acrioceras'-like forms, hemihoplitids, Heteroceras, abundant juvenile
aconeceratids, together with large Sanmartinoceras-like body chambers, Phylloceras
serum (Oppel), Eulytoceras phestum (Matheron) and occasional Colchidites.
Barremian II
Characterized by the occurrence of Colchidites (Colchidites) in vast numbers, with
j uvenile aconeceratids locally common . The only other forms recorded are occasional
Sanmartinoceras, Phylloceras, crioceratid-like fragments and indeterminate ancylo-
ceratids.
APTIAN
'L'etage Aptien' was first used by d'Orbigny in 1840 ; the type locality of the
stage is around Apt, Vaucluse, in southern France. Sornay (1957) reviews early
usage of the name ; the succession in the type area and adjoining regions is dis-
cussed by Taxy et al. (1965), Moullade (i965a, b) and Flandrin (1965). The most
complete review of Aptian biostratigraphy is given by Casey (1961). The classic
definition of the Aptian/Barremian boundary is at the appearance of primitive
deshayesitids, Pseudohaploceras mother oni (d'Orbigny) and Procheloniceras albrechti-
austriae (Hoehnneger in Uhlig). Of these forms, only early cheloniceratids are
known from Zululand, and we have drawn the base of the Aptian below their first
occurrence. Subdivisions of the stage are as follows :
Aptian I
Juvenile cheloniceratids, tentatively referred to Procheloniceras, are abundant.
The only other ammonites known are Tropaeum sp., Ancyloceras sp. and other
ancyloceratid fragments.
ZULULAND AND NATAL 275
Aptian II
Cheloniceras s.s. becomes frequent, and includes forms resembling Cheloniceras
gottschei (Krenkel) and C. aff. proteus Casey, together with larger specimens having
Procheloniceras-like outer whorls. A desmoceratid (Valdedorsella or Pseudohaplo-
ceras) is not uncommon, as are large, poorly preserved ancyloceratids, e.g. Ancylo-
ceras, Tropaeum and Australiceras.
Above this level there may be a non-sequence.
Aptian III
Characterized by an abundance of diverse Acanthoplites species, Diadochoceras ?,
Valdedorsella, Phylloceras, diverse small heteromorphs including Ancyloceras,
Protanisoceras-like and Tonohamites-like forms, and Lytoceras.
Aptian IV
Characterized by an abundance of giant Tropaeum, especially finely-ribbed forms.
Large 'Lytoceras' are common, together with Tonohamites, giant Acanthoplites,
Diadochoceras nodostocatum (d'Orbigny) and related forms.
ALBIAN
'L'etage Albien' was introduced by d'Orbigny in 1842. The type area of the stage
is Aube, Roman Alba, in southern France. Sornay has reviewed previous usage and
interpretation of the stage (1957), whilst Lower Albian stratigraphy is revised by
Casey (1961), the Middle Albian reviewed by Owen (1971) and sections in the type
area and adjacent regions described by Larcher et al. (1965), Destombes & Destombes
(1965), Marie (1965) and Collignon (1965).
The subdivision of much of the type Albian is based upon the typically boreal
hoplitids, which did not range into southern Africa, and as a result correlation with
Europe, especially during the Middle Albian, is difficult. We follow Breistroffer
(1947) and Casey (1961) in placing the 'Clansayes' horizon in the Aptian, taking the
base of the Albian as the base of the European Leymeriella tardefurcata Zone. In
Zululand, as in Madagascar (Collignon 1965), this basal part of the Albian is missing,
and the Aptian/Albian boundary is a non-sequence (Kennedy & Klinger 1972), the
local base of the Albian being marked by the abundance of Douvitteiceras. Sub-
divisions of the stage are as follows :
Albian I - absent
Albian II
Abundant Douvilleiceras, including forms close to D. orbignyi Spath, D. mam-
millatum (Schlotheim) and varieties. Other ammonites are scarce, but include poorly
preserved desmoceratids and lytoceratids.
276 CRETACEOUS FAUNAS
Albian III
Douvilleicems is abundant, but in contrast to Albian II, diverse other ammonites
occur. A Damesites ? sp. nov. is common, whilst Lyelliceras species, including L.
lyelli (d'Orbigny) and L. pseudolyelli (Parona & Bonarelli) are frequent, together
with ' N eosilesites' , Phylloceras (Hypophylloceras) , 'Beaudanticeras' , 'Cleoniceras' and
'Sonneratia' species, Rossalites, Ammonoceratites, abundant Anagaudryceras sacya
(Forbes), Eubrancoceras aff. aegoceratoides (Steinmann) and Oxytropidoceras species.
Albian IV
Oxytropidoceras is common, including subgenera 0. (Oxytropidoceras), 0. (Manuani-
ceras and 0. (Androiavites) . Other ammonites include Pseudhelicoceras, Mojsi-
sovicsia, Phylloceras (Hypophylloceras) velledae (Michelin) and desmoceratids.
Albian V
Characterized by the abundance of mortoniceratids, and the bulk of the faunas
described by van Hoepen for his Umsinene Beds come from this broad division.
Genera present are : Hysteroceras (including Askoloboceras, Komeceras, Petinoceras
and Terasceras van Hoepen), Oxytropidoceras (including Lophoceras van Hoepen),
0. (Tarfayites), D. (Dipoloceras) (including Rhytidoceras, Cechenoceras, Ricnoceras
and Euspectoceras van Hoepen), D. (Diplasioceras) , M. (Mortoniceras), M. (Deira-
doceras), Erioliceras, Arestoceras, Cainoceras, Puzosia, Bhimaites, Desmoceras, P.
(Hypophylloceras}, Anagaudryceras, Gaudryceras, Tetragonites, Hamites, Anisoceras,
Labeceras and Myloceras.
Albian VI
Characterized by the appearance of Mortoniceras (Durnovarites] species, together
with Stoliczkaia species including S. africana (Pervinquiere), S. notha (Seeley) and
S. dorsetensis (Spath), together with abundant Idiohamites, Hamites and Anisoceras
species, with scarcer Lechites, Marietta, Hypengonoceras and puzosiids.
CENOMANIAN
'L'etage Cenomanien' was introduced by d'Orbigny (1847, 1850, 1852) with the
environs of Le Mans, Roman Cenomanum, as the type area. Sornay (1957) has
reviewed the history of various usages of the term whilst Hancock (1959) lists the
ammonite faunas of the type area and other localities in Sarthe. Kennedy &
Hancock (1971) have discussed the problem of the supposed martimpreyi Zone at the
base of the stage, whilst the higher parts of the stage are discussed by Juignet et al.
(1973).
The base of the Cenomanian is drawn at the base of the classic Mantelliceras
mantelli Zone of Hancock (1959), Kennedy (1969-71) and others. It is marked by
the diversification of the Mantelliceratinae ; genera such as Mantelliceras, Sharpei-
ceras, Graysonites, Utaturiceras and Acompsoceras appear, as does Hypoturrilites,
whilst Schloenbachia becomes abundant in the Boreal Realm. In South Africa, we
ZULULAND AND NATAL 277
draw the base of the stage at the incoming of abundant Sharpeiceras and Marietta
oehlerti (Pervinquiere) . Subdivisions of the stage are as follows :
Cenomanian I
Characterized by abundant Sharpeiceras especially S. florencae Spath and S. falloti
(Collignon) , abundant Marietta oehlerti, together with scarcer Desmoceras latidorsatum
(Michelin), Sciponoceras roto Cieslifiski, 5. (Scaphites) cf. simplex Jukes-Browne ?,
Marietta, Ostlingoceras, Hypoturrilites and Mantetticeras.
Cenomanian II
Characterized by a rather more diverse assemblage, Ostlingoceras rorayensis
(Collignon) is common with Hypoturrilites carcitanensis (Matheron), H. gravesianus
(d'Orbigny), H. tuberculatus (Bosc), H. nodiferus (Crick), Marietta spp., Sciponoceras
roto Cieslifiski, Scaphites sp., Desmoceras latidorsatum, Tetragonites subtimotheanus
Wiedmann, Forbesiceras largilliertianum (d'Orbigny) , Sharpeiceras laticlavium (Sharpe)
and Mantetticeras spp. including M. spissum Collignon, M. group of cantianum Spath,
M. patens Collignon, M. indianense Hyatt and a number of desmoceratids.
Cenomanian III
Turrilites acutus Passy is abundant, with scarcer T. costatus Lamarck and T.
scheuchzerianus Bosc. Abundant Acanthoceras spp., including the forms de-
scribed by Crick (igoya) as A.flexuosum Crick, A. crassiornatum Crick, A. munitum
Crick, A . robustum Crick, A . quadratum Crick, A , hippocastanum Crick (non Sowerby)
and A. latum Crick, occur in the lower part of the division, being replaced above by
abundant Calycoceras of the choffati (Kossmat) group, e.g. C. newboldi newboldi
Crick (non Kossmat ?), C. newboldi spinosum Crick (non Kossmat ?), C. newboldi
planecostata Crick (non Kossmat ?) and C. laticostatum Crick. Other ammonites are
Acanthoceras cornigerum Crick, Forbesiceras largilliertianum d'Orbigny, F. sculptum
Crick, Calycoceras gentoni (Brongniart) paucinodatum (Crick) and species of Desmo-
ceras, P. (Hypophylloceras], Borissiakoceras, Anisoceras, Stomohamites, Sciponoceras,
Scaphites, Puzosia and Bhimaites.
Cenomanian IV
Sparsely fossiliferous ; Calycoceras of the choffati group persists, whilst other
ammonites are Calycoceras nitidum (Crick), C. group of naviculare (Mantell) and
Eucalycoceras sp.
The highest parts of the Cenomanian are absent on land in South Africa.
TURONIAN
'L'etage Turonien' was introduced by d'Orbigny in 1842, and amended to its present
limits by him in 1847 and 1850. The type area of the stage is Touraine, Roman
Turonia, between Saumur and Montrichard, France.
278 CRETACEOUS FAUNAS
Sornay (1957) has reviewed the history of the various usages of the stage, whilst
the problems associated with the definition of the base of the Turonian are discussed
by Juignet et al. (1973) and Kennedy & Juignet (1973). The base of the stage
is taken as the base of the classic Inoceramus labiatus/Mammites nodosoides Zone for
the purpose of discussion here, although no Turonian rocks are known on land in
South Africa.
CONIACIAN
'L'etage Coniacien' was introduced by Coquand (1857) with the suburbs of the
town of Cognac in Charente, France, as the type area. Here, the stage consists of
rather poorly fossiliferous calcarenites (Seronie- Vivien 1959, Dalbiez 1959 : 862).
The base of the stage is taken as being at the base of the classic Barroisiceras haber-
fellneri Zone of de Grossouvre (1901), the fauna of which is better known in the Craie
de Villedieu of Touraine (de Grossouvre 1894, 1900), where Barroisiceras, Tissotia,
Peroniceras and other early texanitids typify the Zone.
Barroisiceras, well known in the lowest Coniacian of Madagascar (e.g. Basse 1947,
Collignon 1965), are absent in our faunas, and it may be that the lowermost Coniacian
is absent in South Africa. Instead, our lowest Coniacian yields a sparse fauna of
Collignon's (1965) Middle Coniacian Kossmaticeras theobaldianum and Barroisiceras
onilahyense Zone whilst our higher faunas contain elements typical of this zone and
his Lower Coniacian Peroniceras dravidicum Zone. Our provisional subdivisions of
the stage are as follows :
Coniacian I
Proplacenticeras are abundant including forms named P. kaffrarium (Etheridge),
P. subkaffrarium (Spath) and P. umkwelanense (Etheridge), all of which represent
no more than a single variable species. Other ammonites are Kossmaticeras
theobaldianum (Stoliczka), Bostrychoceras indicum (Stoliczka), Pachydesmoceras
denisonianum (Stoliczka), and P. sp.
Coniacian II
Proplacenticeras are again abundant, with strongly ornamented kaffrarium and
subkaffrarium more frequent than below. Evolute Peroniceras of the tridorsatum
(Schliiter) group are common, e.g. forms named by van Hoepen as P. besairei van
Hoepen ( = Fraudatoroceras besairei van Hoepen) and P. tenuis van Hoepen. For-
resteria are common, e.g. F. alluaudi (Boule, Lemoine & Thevenin), F. razafmiparyi
Collignon, F. vandenbergi van Hoepen, F. reymenti van Hoepen and F. hammersleyi
van Hoepen, all of which represent no more than a single variable species ; other
ammonites are 'Eedenoceras' multicostatum van Hoepen, Forresteria itwebae van
Hoepen, Basseoceras krameri van Hoepen, Kossmaticeras sparsicosta (Kossmat),
K. sakondryense Collignon, Puzosia spp., Pachydesmoceras sp., Lewesiceras australe
van Hoepen, L. spp., Yabeiceras spp., Pseudoxybeloceras matsumotoi Collignon,
Hyphantoceras reussianum (d'Orbigny), Allocrioceras spp., Baculites bailyi Woods,
Scaphites meslei de Grossouvre and 5. spp.
ZULULAND AND NATAL 279
Coniacian III
Placenticeras are common, as below, as are coarsely ornamented peroniceratids,
e.g. van Hoepen's P. (Zuluiceras] : P. (Z.) zulu van Hoepen, P. (Z.) charlei van
Hoepen and their allies (perhaps no more than a single variable species) ; Protexanites
(Protexanites), P. (Miotexanites) and Paratexanites (Paratexanites} species, Baculites
bailyi, Kossmaticeras and Praemuniericeras ? sp.
Coniacian IV
Baculites of the capensis group are abundant, whilst compressed, finely ornamented
peroniceratids, van Hoepen's Peroniceras (Zuhiites] and robustly ornamented
Gauthiericeras 1 , e.g. 'Falsebayites peregrinus van Hoepen, 'Fluminites' albus van
Hoepen, ' Hluhluweoceras' fugitivum van Hoepen and ' Andersonites' listeriv&n. Hoepen,
are locally common.
Coniacian V
The highest Coniacian is not well exposed in Zululand. Above the rather distinc-
tive association of Coniacian IV are beds with abundant Baculites ornamented only
by growth striae, and also yielding ammonites resembling Pseudoschloenbachia
primitiva Collignon, and Scaphites. This appears to be the horizon of Subprionotropis
cricki (Spath).
SANTONIAN
'L'etage Santonien' was introduced by Coquand (1857). The type area is around
the village of Saintes in the northern part of the Aquitaine Basin. The position of the
base of the stage is disputed (see, for instance, Collignon 1959, Wiedmann 1959,
1964, Dalbiez 1959). The classic ammonite zonation of the stage (de Grossouvre
1894, 1901) is :
Placenticeras syrtale Zone
Eupachydiscus isculensis Zone
Texanites texanus Zone
This is based upon the Corbieres succession in southern France ; typical forms of
the texanus Zone in addition to the index species include Parabehavites serratomar-
ginatus (Redtenbacher) and Muniericeras lapparenti de Grossouvre. In South
Africa we have drawn the base of the stage at the level of the appearance of Texanites
s.s. in numbers. Subdivisions are :
Santonian I
Texanites oliveti (Blanckenhorn), T. (Plesiotexanites) stangeri (Baily) densicosta
(Spath), T. (P.) stangeri sparcicosta Spath, Hauericeras gardeni (Baily), Pseudo-
schloenbachia sp., Pseudophyllites indra (Forbes), Karapadites ? sp., Eupachydiscus ?
sp., Gaudryceras spp., Hyphantoceras sp., and diplomoceratids.
25
28o CRETACEOUS FAUNAS
Santonian II
Abundant Texanites (Plesiotexanites) stangeri and varieties, T. soutoni (Baily), T.
spp., Hauericeras and Pseudoschloenbachia occur, as do Eupachy discus ?, Hyphan-
toceras and diplomoceratids.
Santonian III
Hauericeras gardeni is abundant ; the remainder of the fauna is as in Santonian II
and is relatively scarce.
CAMPANIAN
'L'etage Campanien' was first used by Coquand in 1857. The type area of the
stage is in Grand Champagne, in the Aubeterre (Charente) region of Aquitaine.
There are considerable problems associated with the succession in the type area, and
the interpretation of the base of the stage used here is taken from de Grossouvre's
(1901) synthesis of the French ammonite succession, e.g. at the base of the Diplac-
moceras bidorsatum Zone. The correlation of the European sequence with South
Africa is tenuous, and we have drawn the local base of the stage below the level of
abundant Submortoniceras. Subdivisions are :
Campanian I
Submortoniceras woodsi (Spath) and related forms are common ; other ammonites
include Bevahites and Menabites, Hauericeras gardeni, Pseudoschloenbachia, Bostry-
choceras and diplomoceratids.
(There may be an unexposed interval in the lithological and faunal sequence at
this level.)
Campanian II
The texanitid Menabites (Australiella) is abundant in the lower part of this division,
but species including M. (A.) australis (Besaire) and M. (A.} besairei (Collignon)
appear to range throughout, together with Bevahites species. Baculites sulcatus
(Baily) (= Baculites vagina var. Van Hoepeni (Venzo)) is abundant throughout
whilst pachydiscids become common in the higher part of the sequence, e.g. Ana-
pachy discus subdulmensis (Venzo), A. wittekindi (Schluter), A. arialoorensis (Sto-
liczka) , P achy discus manambolensis Basse. Other ammonites are Hoplitoplacenticeras
plasticum plasticum Paulcke, Maorites sp., Neogaudryceras sp., Gaudryceras sp.,
Bostrychoceras sp.
Campanian III
Faunas are sparse, but highly distinctive. A feebly nodose Baculites is abundant,
and giant (up to i m) pachydiscids (probably Eupachydiscus] are very common.
Campanian IV
Saghalinites cola (Forbes) and P. (P achy discus) are common. Other ammonites
are : Gunnarites antarticus (Weller), Nostoceras ? sp., and P achy discus (Neodesmo-
ceras] sp.
ZULULAND AND NATAL 281
Campanian V
Giant Bostrychoceras are abundant, with scarcer Saghalinites and compressed
pachydiscids.
MAASTRICHTIAN
The term 'Calcaire de Maastricht' was first used by Omalius d'Halloy in 1808, but
stratigraphic definition of the stage dates from the work of Dumont (e.g. 1850).
The concept of the stage has changed greatly subsequently, and Dumont's Maastrich-
tian is equivalent to what is now regarded as Upper Maastrichtian. We have thus
followed current European practice, and taken the base of the stage as below the
Pachydiscus neubergicus Zone. It is not at present possible to correlate directly
between the classic European sequence and our South African one ; we have there-
fore drawn the local base of the Maastrichtian below the appearance of abundant
Eubaculites. Our subdivisions of the stage are as follows :
Maastrichtian I
Feebly ornamented to smooth Eubaculites are abundant. Other ammonites are
Saghalinites, Pachydiscus (Neodesmoceras), Menuites, ' Epiphylloceras' and Hoplo-
scaphites.
Maastrichtian II
Coarsely ornamented baculitids of Eubaculites ootacodensis (Stoliczka) type are
abundant. Pachydiscids are also present.
Maastrichtian III
No ammonites. Inoceramid debris abundant.
VII. LOCALITY DETAILS
Detailed logs and stratigraphic accounts plus locality maps for sections studied are deposited
in the Palaeontology Library of the British Museum (Natural History) . Outline locality details
only are given for all but the most important sections in the following pages. Latitude and
longitude are given in every case.
A. PONDOLAND
Loc. i. Cliff and foreshore exposures i km north of the mouth of the Umzamba River, Northern
Transkei, 31° 05' 50" S, 30° 10' 30" E. Umzamba Formation.
AGE. The base of the formation is high in the Coniacian (Coniacian V ?) as indicated by the
presence of Subprionotropis cricki (Spath) ( = Barroisiceras umzambiensis van Hoepen) in the
Basement Bed. The occurrence of abundant Pseudoschloenbachia umbulazi, Hauericeras
gardeni, Texanites soutoni, Texanites stangeri and Inoceramus expansus (Baily) at various levels
above this indicate that horizons up to at least Santonian III, and possibly Campanian I, are
present.
282 CRETACEOUS FAUNAS
Locs 2, 3. Reefs exposed at low water around Trafalgar Beach, between the Mhlangamkulu
and Mpenjati Rivers, Southern Natal (Pondoland), 30° 57' 50" S, 30° 18' oo" E. Umzamba
Formation.
AGE. Loc. 2 lies close to the base of the succession and yielded abundant Santonian Spheno-
ceramus. Loc. 3, higher in the succession, is probably Campanian, yielding Kossmaticeras
(Natalites) and B acuities sulcatus. Pseudoschloenbachia umbulazi has been recorded from this
area (Crick igoyb, Spath ig22a).
B. DURBAN
Loc. 4. Excavations for the new Magistrates' Court on Sometsu Road, Durban. Umzamba
Formation.
AGE. Campanian II ? It seems likely that more than one horizon is represented in the
collection.
Loc. 5. Excavations for the new sugar terminal at May don Wharf, Durban Bay. Umzamba
Formation.
AGE. Santonian III and Campanian I ? Several horizons are clearly represented.
C. KWA-MBONAMBI, ZULULAND
Loc. 6. Excavations (1971) for new bridge over the Nyokaneni River, west of the Mtubatuba-
Empangeni road, south of Empangeni, 28° 41' 14" S, 32° 01' 22" E. St Lucia Formation.
AGE. Santonian II-III, Campanian I.
D. MFOLOZI AND UMKWELANE HILL, ZULULAND
In this region (Fig. 2), Cretaceous sediments are largely obscured by Tertiary and Quaternary
deposits (Fig. 3). Outcrops are limited to strips along the flanks of Lake Teza, followed by the
railway (with most exposures in cuttings), and the north bank of the Mfolozi, below Riverview
as far east as Monzi.
Locs 7, 8. Small cuttings alongside the track leading from the Mtubatuba Club towards
Mains Farm (Frankel 1960 : 236, fig. 3), south of Mtubatuba, 28° 26' 38" S, 32° 10' 20" E and
28° 26' 34" S, 32° 10' 22" E respectively. Makatini and St Lucia Formations.
AGE. The Makatini conglomerates and sandstones at these localities cannot be dated more
precisely than Lower Cretaceous. The base of the St Lucia Formation is Lower Coniacian,
probably Coniacian II.
Loc. 9. Railway cutting 100 m north of Lake View siding, 28° 29' 18" S, 32° 08' 45" E, on the
western side of Lake Teza, south of Mtubatuba. St Lucia Formation. These cuttings expose
the contact between the Cretaceous and metamorphic and granitic Basement. The contact is
sharp, with a basal Cretaceous conglomerate with boulders of granite and schist up to 30 cm
long, set in a matrix of bioclastic limestone. Above are 3 m of hard shelly limestone with softer
lenticles, both crowded with oysters, cidarid spines and plates.
AGE. Coniacian.
Loc. 10. Railway cutting i-i km north of Haig Halt, 28° 27' 40" S, 32° 09' 58" E on the eastern
flank of Umkwelane Hill, south of Mtubatuba. St Lucia Formation. This is locality d of du
Toit (in Spath i92ia), also mentioned by Besaire (1930 : 619) and others. The St Lucia Forma-
tion, dipping eastwards at i° to 2°, rests on an undulating surface of deeply- weathered basalt
dipping 70° S. The base of the sequence is a tough, buff, sandy and silty limestone, with scat-
tered quartz and quartzite pebbles, abundant oysters, other molluscs and cidarid spines. Perhaps
20 m of alternations of deeply weathered silts and layers of intensely hard concretions with drifted
shelly lenticles are exposed above this. There is a diverse molluscan fauna, dominated by bi-
valves and gastropods. Concretions 3 m above the base yielded Proplacenticeras umkwelanense,
Forresteria alluaudi and a scaphitid. Besaire (1930 : 619, 634, pi. 26, fig. 4) described a Peroniceras
ZULULAND AND NATAL 283
from this locality, and Spath records Proplacenticeras subkaffrarium, Diaziceras tissotiaeforme
Spath and other species.
AGE. The presence of Proplacenticeras suggests a Coniacian age for the base of the sequence.
Loc. II. Road cut on the north side of the new road from road N 14 to Haig Halt, Umkwelane
Hill, south of Mtubatuba, 20° 28' 22" S, 32° 09' 32" E. St Lucia Formation.
AGE. The presence of Proplacenticeras suggests a Coniacian age for the sequence.
Loc. 12. A small quarry 300 m SSE of the previous section, south of the road and north of the
railway near Haig Halt, Umkwelane Hill, south of Mtubatuba, 28° 28' 31" S, 32° 09' 34" E.
St Lucia Formation.
AGE. Coniacian.
Loc. 13. Hill slopes below Riverview Compound, 750 m north of the Cane Railway Bridge
across the Mfolozi, south of Mtubatuba, 28° 26' 52" S, 32° 10' 48" E. St Lucia Formation.
AGE. Coniacian II -III ; as indicated by species of Proplacenticeras, Peroniceras, Forresteria,
Scaphites, Baculites, kossmaticeratids, puzosiids and diplomoceratids.
Loc. 14. Road cuttings below the compound immediately south of the Msunduzi River,
2-1 km NNE of Mfolozi, south of Mtubatuba, 28° 28' 24" S, 32° 10' 43* E. St Lucia Formation.
AGE. Santonian II and III, Campanian I.
Loc. 15. Small quarry east of track on lot 71 13567, 1200 m east of Riverview Sugar Mill,
south of Mtubatuba, 28° 26' 35* S, 32° n' 24" E. St Lucia Formation.
AGE. Coniacian IV.
Loc. 16. Small quarry 175 mSSEof loc. 15 ; 28° 26' 42* S, 32° n' 25" E. St Lucia Formation.
AGE. Coniacian III ?
Loc. 17. Cuttings in cane road leading down to Peaston North Bank Drain on lot 72 13569,
350 m south of the farm Pasina, SE of Mtubatuba, 28° 26' 04" S, 32° n' 48" E. St Lucia
Formation.
AGE. Coniacian V.
Loc. 1 8. Outcrops in cane road leading down to Peaston North Bank Drain on lot 47 12967,
1200 m SE of the farm Chelmsford, ESE of Mtubatuba, 28° 26' 38" S, 32° 12' 38" E. St
Lucia Formation.
AGE. Santonian.
Loc. 19. Road cutting west of Lake Mfuthululu on Shire Estate, leading down to Peaston
North Bank Drain, ESE of Mtubatuba, 28° 25' 39* S, 32° 14' 45" E. St Lucia Formation.
AGE. Campanian I.
Loc. 20. Section at junction of the old course of the Mfolozi, the present river and the unnamed
stream draining south from Lake Mfuthululu, ESE of Mtubatuba, 28° 26' 59" S, 32° 16' 36* E.
St Lucia Formation.
AGE. Maastrichtian I -II.
Loc. 21. Roadside section 9 km north of Monzi, east of Mtubatuba, 28° 25' oo* S, 32° 18' 35" E.
St Lucia Formation.
AGE. Campanian V.
E. THE NYALAZI RIVER, SOUTH OF HLUHLUWE, ZULULAND
North of Mtubatuba, exposures are poor, due to an extensive cover of Tertiary and Recent
deposits. Such sections as are visible are deeply decalcified and often barren of recognizable
macrofossils. There are, however, a series of exposures along the Nyalazi River which give a
discontinuous sequence from Karoo sediments and Lebombo Volcanics through to the St Lucia
Formation.
26
284 CRETACEOUS FAUNAS
Loc. 22. Cut on the north side of the Nyalazi River, east of the old Nyalazi road and railway
bridge, 2 km north of the Nyalazi River Trading Store, 28° 12' 23" S, 32° 18' 02" E. St Lucia
Formation.
AGE. Coniacian IV.
Loc. 23. Stream exposures 1-4 km NW of the old Nyalazi bridge, 28° 12' 05* S, 32° 17' 01" E.
St Lucia Formation.
AGE. Coniacian III ?
Loc. 24. Cuttings and excavations at the new Nyalazi River bridge in Moroval 1884 section,
28° 14' 27" S, 32° 17' 37" E. St Lucia Formation.
AGE. Coniacian II -V.
Loc. 25. Cutting alongside new road 2-8 km ESE of Nyalazi River trading store, 28° 13' 42" S,
32° 1 6' 48" E. St Lucia Formation.
AGE. Coniacian II.
Loc. 26. River banks on NE side of the Nyalazi, i km ENE of the old combined road/rail
bridge 28° 12' 12" S, 32° 18' 42" E. St Lucia Formation.
AGE. Santonian ?
Loc. 27. Trackside exposures leading down to the eastern bank of the Nyalazi 1-25 km SE of
the old bridge, 28° 12' 35" S, 32° 18' 44" E. St Lucia Formation.
AGE. Campanian I.
Loc. 28. Abandoned quarry on southern side of Nyalazi River trading store -Charters Creek
track i -3 km east of the store, 28° 13' 12" S, 32° 19' 10" E. St Lucia Formation. Scattered
exposures of Campanian silts occur for several kilometres along the Nyalazi downstream of this
locality.
AGE. Campanian.
Loc. 29. Excavations by abandoned dam on Cekeni Estate 2-9 km ESE of Mfekayi Halt,
28° 10' 54" S, 32° 20' 05" E. St Lucia Formation.
AGE. Campanian I -II.
Loc. 30. Overgrown hill slopes on the western side of the Nyalazi River in Bantu Reserve
No. 3, 5 km east of Glenpark Estate, 28° 07' 52" S, 32° 20' 56" E. St Lucia Formation.
AGE. Campanian I -II.
Loc. 31. Gullies and hill slopes on west bank of Nyalazi in Bantu Reserve No. 3, 6 km ENE of
Glenpark Estate, 28° 07' 12" S, 32° 21' 47" E. St Lucia Formation.
AGE. Santonian.
F. GLENPARK ESTATE, ZULULAND
Sections along the lower Hluhluwe are poor, but exposures along the railway on Glenpark
Estate prove definitely the presence of Albian sediments. Cenomanian faunas are unknown,
but there is a very complete Coniacian sequence exposed to the NE (p. 295). Although not
proven, the base of the St Lucia Formation may rest upon Upper Albian Mzinene Formation
in this area.
Loc. 32. Cutting in acute bend of railway west of Glenpark Estate, n km south of Hluhluwe,
28° 07' 55" S, 32° 17' 18" E. Mzinene Formation.
AGE. Albian III.
Loc. 33. Railway cuttings west of Glenpark Estate, n km south of Hluhluwe, 28° 07' 50" S,
32° 17' 39" E. Mzinene Formation.
AGE. Albian IV.
ZULULAND AND NATAL 285
G. THE MZINENE RIVER AND ITS TRIBUTARIES, ZULULAND
(i) Upper reaches
The Mzinene and its tributaries provide a discontinuous succession from the Lebombo Vol-
canics and pre-Upper Aptian elastics of the Makatini Formation to the Upper Coniacian and
perhaps Lower Santonian St Lucia Formation. It is the type section of the Mzinene Formation
and the base of the succeeding St Lucia Formation.
Sections along the tributary streams are poor, and those along the main river are usually
below water, because of extensive damming. Bilharzia and crocodiles (see du Toit and van
Hoepen 1929) render these sections rather inaccessible, but extensive droughts prior to our
visit had reduced water levels and raised salinities so much that we were able to see far more of
this section than is usually exposed, and collect important faunas from the lower parts of the
Upper Albian.
Dips in this area are low, of the order of 2°-6°, and it is difficult to measure the thickness of the
sequence when exposures are limited to the stream bed. Cliff exposures are available, but are
often deeply weathered and choked by thorn and scrub. Some additional exposures are
available in old river cliffs, as at the Skoenberg, and south of the kraal in Ndabana 13162 sec-
tion, but these are deeply decalcified and the fossil fauna lies loose on hill slopes.
Loc. 34. Cliff and stream section 600 m north of the farm Amatis, just to NE of the confluence
of the Mzinene and an un-named, eastward-flowing tributary, north of Hluhluwe, 27° 58' 32" S,
32° 1 8' 02" E. Makatini Formation.
AGE. Aptian IV.
Loc. 35. Cliff and stream sections extending over several hundred metres along the Mzinene,
approximately 1200 m NE of the farm Amatis, north of Hluhluwe, 27° 58' 03" S, 32° 18' 31" E.
Mzinene Formation.
AGE. Albian III.
Loc. 36. Degraded river cliff on the eastern bank of the Mzinene close to the boundary of lots
H 84 14107 and H 85 14108, north of Hluhluwe, 27° 57' 14" S, 32° 18' 34* E. Mzinene
Formation.
AGE. Albian III.
Loc. 37. Discontinuous exposures in the bed of the Mzinene over a distance of some 600 m in
lots H 86 13655 and H 87 13656, north of Hluhluwe, 27° 56' 37" S, 32° 18' 08" E. Makatini
Formation.
AGE. Aptian IV.
Locs 38-43. North of loc. 37, the Mzinene swings west in a long meander, crossed by the road
running east from the National Road N 14, just north of Ngweni. In this region, there are a
series of exposures in the Makatini Formation, with hills of Lebombo Volcanics rising to the east.
Makatini Formation.
Loc. 38. 27° 56' 09" S, 32° 18' 03" E. Loc. 41. 27° 55' 42" S, 32° 17' 50" E.
Loc. 39. 27° 55' 57" S, 32° if 44" E (Plate, Fig. i). Loc. 42. 27° 55' 38" S, 32° 17' 02" E.
Loc. 40. 27° 55' 58" S, 32° if 58" E. Loc. 43. 27° 55' 20" S, 32° 18' 10" E.
AGE. Pre-Upper Aptian. No ammonites or other diagnostic fossils are known.
Loc. 44. Stream section 900 m SE of Baboon's Krans, north of Hluhluwe, 27° 54' 24" S,
32° if 48" E.
AGE. Pre-Upper Albian.
Locs 45-49. Stream and river cliff exposures extending downstream from the drift where the
minor road leading north from the sisal factory to Monte Rosa crosses the Mzinene, 27° 53' 59" S,
32° 1 8' 06" E to 27° 53' 50" S, 32° 19' 10* E. Makatini Formation.
AGE. Pre-Upper Aptian.
Silts
Concretions with mortoniceratids
Well-exposed bioturbated silts with
an abundant drifted and in-situ
molluscan fauna
Concretions with many molluscs:
small Mortoniceras and Anagaudryceras
common, also PuzoTia, Myloceras and
many bivalves
Poorly exposed bioturbated silts
Concretionary shell limestone.
Abundant trigoniids, Veniella, Gervillella,
Pholadomya, Exogyra, Margarites ,
Hysteroceras , Myloceras
Poorly exposed silts
Concretions, Pholadomya vignesi,
Goniomya, Veniella, trigoniids,
Poorly exposed silts with drifted
bivalves. Hysteroceras and
mo rton i ce ra tids frequent
Poorly exposed bioturbated silts
Concretions with many molluscs,
especially large Mortoniceras and
nautiloids, trigoniids, Gervillella,
Protocardia and other heterodonts
6
v5-r*^:r
5
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—
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&$Z£
3
T~
!><§
iifeSS
~1~
3^2
Poorly exposed bioturbated silts
Concretions with giant Hortoniceras,
Myloceras and drifted bivalves
Concretions crowded with drifted
molluscs: Entolium, trigoniids,
Veniella, Pholadomya, oysters, Modiolus,
Glycymeris etc. Abundant Dlpolpceras ,
Puzosla.Tabeceratids , P_. (Hypophylloceras)
Poorly exposed silts
Concretionary shell bed, crowded with
molluscs: Entolium. Pterotrigonia and
Pholadomya vignesi abundant. Dlpoloceras,
Labeceras, Myloceras
Poorly exposed rusty concretions with
occasional ammonites and many drifted
bivalves: Gervi llella, Pterotri gonia,
Veniella, Inoceramus, Pholadomya
Poorly exposed bioturbated silts
Concretions and shell bed. Abundant
Hemi aster, Neithea, Exogyra, Pterotrigonia,
Veniella, venerids and other heterodonts.
Anrooni tes include Oiploceras
Poorly exposed bioturbated silts.
Hemi aster abundant at top
Concretions with occasional Gervi llella
and trigoniids. Hami tes common
Poorly exposed bioturbated silts
Winnowed shell bed with scattered pebbles.
Abundant thick-shelled bivalves: Veniella,
Gervillella, trigoniids, oysters.
Ammonites include Mojsisoyicsia,
Oxy tropi doce ras , Pseudoheli coceras , Puzosia
and P.(Hypophylloceras). Logs
3ft
Vertical Scale is approximate only
FIG. 4. The sequence at loc. 51.
Proplacenticeras common in soil
6. Deeply weathered yellow-buff silts with concretions, silicified logs and
scattered molluscs. Proplacenticeras kaffrarium, P.subkaffrarium,
P.umkwelanense
5. Deeply weathered yellow-buff cross-bedded fine sandstones with courses of
calcareous concretions, occasional shelly lenticles and silicified logs.
The fauna includes Glycymeris. diverse heterodonts, Proplacenticeras
species as above, Bostrychoceras indi cum, Pachydesmoceras denisonianum
and Pachydesmoceras sp.
***^%i.%*<i.<«i NON-SEQUENCE ^ "° ^
3. Decalcified yellow-buff concretions, upper surface bored by Li thophaga
2. Shell bed below yields abundant minute gastropods, together with
Pterotrigonia, diverse venerids, Pleuromya, Neithea, arcids and Hemi aster
1. Buff, flaggy-weathering decalcified silts with spheroidally weathering
concretions. Cylindrical arthropod burrows conspicuous, but body fossils
scarce. Calycoceras of the choffati group picked up from scree slopes
f4. Pterotrigonia conglomerate: igneous pebbles, agates, bivalve debris,
abundant Pte rot ri goni a shepstonei and rare Proplacenticeras
FIG. 5. The sequence at loc. 60.
288 CRETACEOUS FAUNAS
Loc. 50. Outcrops in the river bed north of the earth dam 1200 m ENE of the sisal factory,
where the track to the farm Belvedere approaches the Mzinene, north of Hluhluwe, 25° 53' 50* S,
32° 19' 10" E. Makatini Formation.
AGE. Aptian.
Loc. 51. Stream bed and bank exposures extending 100-600 m downstream from loc. 50,
around the eastern limb of the broad meander ENE of the sisal factory, north of Hluhluwe,
27° 53' 43* S, 32° 19' 22" E (Fig. 4). Mzinene Formation.
AGE. Albian IV-V.
Loc. 52. West bank of the Mzinene just north of a gully entering from the west in Indabana
13162 section, north Hluhluwe, 27° 53' 04" S, 32° 19' 21" E. Mzinene Formation.
AGE. Albian V.
Loc. 53. Derelict dam site on Indabana 13162, 2-2 km south of the farm Izwehelia, north of
Hluhluwe, 27° 52' 24" S, 32° 19' 02* E. Mzinene Formation.
AGE. Albian III.
Loc. 54. Degraded river cliff 200-350 m west of south-trending gully which joins the Mzinene
in Munywana 13161 section, close to where the river turns sharply eastwards north of Hluhluwe,
27° 52' 46" S, 32° 19' 40" E. Mzinene Formation.
AGE. Albian V.
Loc. 55. Sections in the gully immediately east of the previous locality, 500 m north of its
junction with the Mzinene in Munywana 13161 section, 27° 52' 26* S, 32° 19' 42* E. Mzinene
Formation.
AGE. Albian V.
Loc. 56. Degraded river cliffs immediately east of loc. 55, in Munywana 13161 section, 27°
52' 30" S, 32° 19' 44" E. Mzinene Formation.
AGE. Albian V.
Loc. 57. Outcrops in the bed of the Mzinene at Beacon 624, where the river swings east in
Munywana 13809 section, north of Hluhluwe, 27° 52' 40" S, 32° 19' 58" E. Mzinene Formation.
AGE. Albian V.
Loc. 58. Degraded cliff on the north bank of the Mzinene in Iswelihle 13163 section WNW of
the farm Belvedere, NNE of Hluhluwe, 27° 52' 42" S, 32° 20' 36" E. Mzinene Formation.
AGE. Albian V.
Loc. 59. Section on eastern side of swamp at the mouth of a gully draining south to the
Mzinene from the Skoenberg in Iswelihle 13163 section, 1200 m NNW of the farm Belvedere,
NNE of Hluhluwe, 27° 52' 41" S, 32° 20' 45" E. Mzinene Formation.
AGE. Cenomanian III.
Loc. 60. River cliff and river bed outcrops extending for several hundred metres along the north
side of the Mzinene in Iswelihle 13163 section, 1000 m NNW of the farm Belvedere, north of
Hluhluwe, 27° 52' 45" S, 32° 20' 55" E (Fig. 5). Mzinene and St Lucia Formations.
AGE. Mzinene Formation : Cenomanian III -IV ; St Lucia Formation : Coniacian I.
(ii) The Skoenberg region
The Skoenberg, in Iswelihle 13163, NNW of Hluhluwe, is a crescentic hill lying between the
Mzinene and Munywana (Manuan of early workers) . The steep NW face rises to over 30 m at
the western end ; to the east it falls to the level of the flood plain. It represents an abandoned
river cliff of the Munywana, which now flows across the northern part of its flood plain at this
point, 700 m from the old cliff.
ZULULAND AND NATAL 289
This is the celebrated locality described by William Anderson in 1907 (p. 60) as situated near
the junction of the Manuan and Mzinene Rivers. It is the source of the rich Cenomanian fauna
described by G. C. Crick in 1907, and the type locality of van Hoepen's Skoenberg Beds.
The hill itself is capped by a veneer of Pleistocene debris, including dark brown, glazed rock
fragments and derived Senonian fossils. The NW cusp of the hill is capped by the Coniacian
Pterotrigonia conglomerate (Anderson's 1907 : 60 'hard calcareous sandstone full of broken
shells'). This dips gently to the east, at first forming the rim to the north face of the Skoenberg,
and then crossing down the face to disappear below the alluvium of the Munywana/Mzinene
flood plain.
There are good exposures of the silts above and below the conglomerate along the main face
of the Skoenberg, whilst to the west gullies and hill slopes provide a magnificent series of ex-
posures, extending down to the Upper Albian. These correspond to localities 5-8 of van
Hoepen (i966a, b).
Loc. 61. Hill slopes and gullies west of the western 'horn' of the Skoenberg, 27° 52' 19*8,
32° 20' 19* E (Fig. 6). Mzinene Formation.
AGE. Albian VI -Cenomanian II.
Loc. 62. Hill slopes at, and extending west from, the western end of the Skoenberg, 27°
52' 17" S, 32° 20' 26" E (Fig. 7). Mzinene and St Lucia Formations.
AGE. Mzinene Formation : Cenomanian II -IV ; St Lucia Formation : Coniacian I.
Loc. 63. The steep, northern face of the scarp of the Skoenberg, 27° 52' 15" S, 32° 20' 30" E.
St Lucia Formation.
AGE. Coniacian I.
(iii) Sections along the Munywana
In Munywana 13161 section, NNE of Hluhluwe, Zululand.
Loc. 64. River cliff on the south side of the main southern tributary of the Munywana, 1-5 km
ESE of the farm Izwehelia, 27° 51' 36" S, 32° 19' 41" E. Mzinene Formation.
AGE. Albian V.
Loc. 65. Dam site excavation and adjacent hillside 200-300 m west of the previous locality
and 1300 m SW of the farm Izwehelia, 27° 51' 38" S, 32° 19' 30* E. Mzinene Formation.
AGE. Albian V.
Loc. 66. River-bed and cliff sections extending for some 400-500 m along the northern branch
of the Munywana north of a point 1-5 km east of the farm Izwehelia and just south of a group
of native huts, 27° 51' 16" S, 32° 19' 44" E. Mzinene Formation.
AGE. Albian V.
Loc. 67. Poor exposures in the north bank of the gully 600 m SSW of the farm Izwehelia,
27° 51' 3?" S, 32° 19' 01" E. Mzinene Formation.
AGE. Albian.
Loc. 68. North bank of gully 300 m SW of the farm Izwehelia, 27° 51' 32* S, 32° 19' 03* E.
Mzinene Formation.
AGE. Albian II.
Loc. 69. Densely vegetated outcrop in gully 600 m ESE of the farm Izwehelia, 27° 51' 29" S,
32° 19' ii* E. Mzinene Formation.
AGE. Albian II.
Loc. 70. Excavations for a dam site 500 m east of the farm Izwehelia, 27° 51' 20* S, 32°
19' 04" E. Mzinene Formation.
AGE. Albian II.
ZULULAND AND NATAL
291
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292 CRETACEOUS FAUNAS
(iv) Lower reaches
In Umzigi 13809 section, NNE of Hluhluwe, Zululand.
Loc. 71. Degraded river cliffs on the north bank of the Munywana Creek, north of the Skoen-
berg, 3 km SW of the farm Insleep, and just west of the earth dam 400 m west of the causeway
across the Mzinene just below the confluence with the Munywana, 27° 51' 48" S, 32° 21' 08" E.
St Lucia Formation.
AGE. Coniacian I.
Loc. 72. Degraded river cliff and alluvial flats on the north side of the Mzinene, 200-300 m
east of the causeway across the river, downstream from its junction with the Munywana,
27° 51' 52" S, 32° 21' 34" E. St Lucia Formation.
AGE. Coniacian IV- V, Santonian I ?
H. SECTIONS AROUND FALSE BAY AND LAKE ST LUCIA, ZULULAND
The False Bay and Lake St Lucia Game Reserves form a lagoon 80 km long, separated from
the sea by dunes up to 200 m high. The lake is nowhere more than a few metres deep and
drains to the sea via the Narrows, 16 km to the south. During drought or when the entrance
to the Narrows is blocked, the lake level falls and salinity rises steeply, accompanied by mass
mortality of the bulk of the invertebrate fauna. During floods, the lake becomes temporarily
freshwater.
Four principal rivers drain into the lake, the Mzinene, Mkuze, Hluhluwe and Nyalazi. Each
has an associated swampy flood plain at its mouth, several miles across. The flood plains and
the lake itself are flanked by cliffs up to 30 m high. These are, for the most part, degraded
and heavily vegetated, but locally expose vertical sections of Cretaceous silts and concretionary
horizons over stretches of several hundred metres. Foreshore platforms are cut in the Upper
Cretaceous at many localities ; extreme drought during our visit exposed many normally sub-
merged outcrops. Elsewhere, saltmarsh and saline pans extend from degraded cliffs to the lake
shore, masking the Cretaceous.
The dip is low, perhaps 3° just south of east, and as a result many exposures approximate to
strike sections.
We have been able to collect and measure sections along the western shores of False Bay,
around the southern termination of the Nibela Peninsula, along the SW shores of Lake St
Lucia, and around the southern peninsula.
(i) Western False Bay
Loc. 74. 1400 m stretch of cliff and foreshore section at Die Rooiwalle, 1-3 km east of the farm
Mfomoto, northern part of False Bay, NNE of Hluhluwe, 27° 54' 12" S, 32° 23' 47* E to
24° 54' 48" S, 32° 23' 15" E (Fig. 8). St Lucia Formation.
AGE. Santonian I-Campanian I.
Locs 75-77. Gullies in degraded cliffs 300 m, 1200 m and i7oom respectively south of Die
Rooiwalle, and inland of an extensive saline pool, NW shores of False Bay, NE of Hluhluwe.
St Lucia Formation.
Loc. 75. 27° 54' 57* S, 32° 23' 07" E. Loc. 77. 27° 55' 04" S, 32° 22' 56" E.
Loc. 76. 27° 55' 19* S, 32° 22' 49" E.
AGE. Coniacian V.
Loc. 78. Foreshore platform 4 km north of Lister's Point and 3-1 km east of the farm Onder-
deel, NW shores of False Bay, NE of Hluhluwe, 27° 56' 02" S, 32° 22' 54* S. St Lucia Forma-
tion.
AGE. Santonian I -II.
ZULULAND AND NATAL
293
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Loc. 79. Degraded cliff section at the northern end of the coastal track lyoom north of
Lister's Point, NW shores of False Bay, NE of Hluhluwe, 27° 57' og" S, 32° 22' 36" E. St
Lucia Formation.
AGE. Coniacian V.
Loc. 80. Foreshore reefs alongside camp site, 600 m north of Lister's Point, western shores of
False Bay, NE of Hluhluwe, 27° 57' 43" S, 32° 28' 38* E. St Lucia Formation.
AGE. Coniacian V.
Loc. 8 1. Foreshore platforms west of Lister's Point, western shores of False Bay, NE of
Hluhluwe, 27° 58' 14* S, 32° 27' 26" E. St Lucia Formation.
AGE. This locality extends across the strike. Faunas from the western outcrops are un-
doubtedly Coniacian IV-V. To the east, higher horizons may be present.
Loc. 82. Foreshore platforms at the end of the small promontory 1-3 km SW of Lister's Point,
western shores of False Bay, NE of Hluhluwe, 27° 58' 38" S, 32° 22' 20* E. St Lucia Formation.
AGE. Coniacian IV.
Loc. 83. Foreshore exposures extending around the headland 3-5 km north of Picnic Point
and known locally as Mason's Camp, western shores of False Bay ENE of Hluhluwe, 28°
oo' 18* S, 32° 22' 20" E. St Lucia Formation.
AGE. Coniacian IV.
Loc. 84. Beach exposures and low cliff 3-2 km north of Picnic Point, SW shores of False Bay,
east of Hluhluwe, 28° 01' oo" S, 32° 22' 08* E, St Lucia Formation.
AGE. Santonian I.
Loc. 85. Low cliff and foreshore exposures extending from 1200 to 1800 m north of Picnic
Point, SW shores of False Bay, east of Hluhluwe, 20° 01' 17" S, 32° 22' 08" E. St Lucia
Formation.
AGE. Santonian I.
Loc. 86. Line of concretions striking across the foreshore 750 m north of Picnic Point, SW
shores of False Bay, east of Hluhluwe, 28° 01' 45" S, 32° 22' 03" E. St Lucia Formation.
AGE. Coniacian V- Santonian I or II.
(ii) The Hluhluwe flood plain
South of Picnic Point, the alluvial flats of the Hluhluwe extend out into False Bay, and there
are no major exposures for several miles down the coast. Instead, outcrops are limited to poor
sections and loose boulders along the river cliffs on the sides of the Hluhluwe. This area is of
some importance, being the type locality of van Hoepen's (1926 onwards) Peroniceras Beds,
and the source of many Coniacian ammonites described by him (i966a-c). The cliffs run
oblique to the strike, and progressively lower horizons appear to the SW.
(a) Western side
Loc. 87. Boulders and concretions littering hill slopes just east of the point where the track to
Picnic Point descends to the flood plain of the Hluhluwe, ESE of Hluhluwe Village, 28° 02' 10" S,
32° 21' 55" E. St Lucia Formation.
AGE. Santonian I.
Loc. 88. Loose boulders and concretions littering slopes over a radius of 200 m from 150 m
west of the point where the track to Picnic Point descends to the flood plain of the Hluhluwe,
ESE of Hluhluwe Village, 28° 02' 12* S, 32° 21' 40" E. St Lucia Formation.
AGE. Coniacian IV-V, perhaps also Santonian I ?
ZULULAND AND NATAL 295
Locs 89, 90. Boulder- and concretion-strewn slopes east and west respectively of the gully
250 m east of the western boundary of the St Lucia Game Reserve, ESE of Hluhluwe Village,
28° 02' 16* S, 32° 21' 19" E to 28° 02' 20* S, 32° 21' n* E. St Lucia Formation.
AGE. Coniacian IV.
Loc. 91. Degraded river cliffs and artificial cut extending over 200 m west of the boundary
fence of the St Lucia Game Reserve and lot H 103 13368, ESE of Hluhluwe Village, 28°
02' 21" S, 32° 21' 02" E. St Lucia Formation.
AGE. Coniacian IV or V.
Loc. 92. Bulldozer scrapings and adjacent hill slopes around the pumping station at the
southern end of the track leading south from the farm Panplaas, on lot H 102 13364, ESE of
Hluhluwe Village, 28° 03' 07" S, 32° 20' 10" E. St Lucia Formation.
AGE. Coniacian II and III.
Loc. 93 Hill slopes extending 200 m on either side of the boundary fence of lots H 102 13364
and H 101 3046, 1600 m SE of the farm Ncedomhlope, ESE of Hluhluwe Village, 28° 03' 19" S
32° 20' oo* E. St Lucia Formation.
AGE. Coniacian II.
(b) Eastern side
Locs 94-96. Shore outcrops SE of the end of the track running north of Nkundusi, ESE of
Hluhluwe, 28° 03' 50" S, 32° 21' 46* E. St Lucia Formation.
AGE. Coniacian V and Santonian I.
Loc. 97. Cliff section 2 km NE of Nkundusi, SE of Hluhluwe, 28° 04' 42" S, 32° 22' 32" E.
St Lucia Formation.
AGE. Santonian.
Loc. 98. Hill slopes alongside track leading north from Nkundusi, 2-0-2-3 km north of the
village, SE of Hluhluwe, 28° 04' 12* S, 32° 21' 14" E. St Lucia Formation.
AGE. Coniacian V ?
Loc. 99. Hill slopes alongside the track running north from Nkundusi, i -0-1-5 km north of
the village, SE of Hluhluwe, 28° 04' 37" S, 32° 21' 26" E. St Lucia Formation.
AGE. Coniacian V.
Loc. 100. Hill slopes alongside track leading north from Nkundusi, 1-3 km north of the village,
SE of Hluhluwe, 28° 04' 47" S, 32° 21' 27" E. St Lucia Formation.
AGE. Santonian I.
Loc. 101. Slopes 250 m south of loc. 100, 28° 04' 57" S, 32° 21' 26" E. St Lucia Formation.
AGE. Santonian II or III.
(iii) False Bay : SE shores
Loc. 102. Cliff exposure at SE end of False Bay east of Nkundusi, and SE of Hluhluwe,
28° 05' 18* S, 32° 23' 02* E. St Lucia Formation.
AGE. Campanian I or II ?
Loc. 103. Hill slopes 1-6 km NNE of the mouth of the Nyalazi, SE of Hluhluwe, 28° 04' 42* S,
32° 23' 37* E. St Lucia Formation.
AGE. Campanian II ?
Loc. 104. Cliff and foreshore exposures 2-3-2-7 km NNE of the mouth of the Nyalazi, SE of
Hluhluwe, 28° 04' 12* S, 32° 23' 38* E. St Lucia Formation.
AGE. Santonian II.
2g6 CRETACEOUS FAUNAS
Loc. 105. Cliff section 3-5 km north of the mouth of the Nyalazi, ESE of Hluhluwe, 28°
03' 27" S, 32° 23' 08* E. St Lucia Formation.
AGE. Santonian III to Campanian I.
Loc. 106. Cliffs 4-2 km north of the mouth of the Nyalazi, ESE of Hluhluwe, 28° 03' 06" S,
32° 23' 16" E. St Lucia Formation.
AGE. Campanian I.
Loc. 107. Loose concretions on shore 400 m north of loc. 106, ESE of Hluhluwe, 28°
02' 45" S, 32° 23' 26" E. St Lucia Formation.
AGE. Campanian ?
Loc. 108. Foreshore exposures 6 km north of the mouth of the Nyalazi, east of Hluhluwe,
28° 02' 21" S, 32° 23' 32" E. St Lucia Formation.
AGE. Campanian I.
(iv) The Nibela Peninsula
This area is a Native Reserve, access is restricted, and we have only visited the southern
coast. For long stretches this is a dip section across interbedded silts and concretions dipping
at approximately 3° just south of east. Exposures consist of vertical cliffs up to 25 m high,
capped by Miocene(?) and Pleistocene sediments, and broad foreshore exposures.
From the SW corner of the peninsula, and running northwards, the cliffs are degraded. We
have not examined this area, rather relying on material in the South African Survey (van
Hoepen Collection), nor have we examined the eastern side.
Loc. 109. Foreshore exposures at the SW tip of the Nibela Peninsula, 27° 59' 03" S, 32°
24' 36" E. St Lucia Formation.
AGE. Campanian II.
Loc. no. 150 m stretch of cliff and foreshore section at the SW tip of the Nibela Peninsula,
27° 59' I0" S, 32° 24' 34" E (Fig. 9). St Lucia Formation.
AGE. Campanian III.
Loc. in. Cliff section just east of the southernmost tip of the Nibela Peninsula, 27° 59' 30" S,
32° 25' 26" E. St Lucia Formation.
AGE. Campanian III.
Loc. 112. Foreshore exposures 1-4 km north of Hell's Gate, Nibela Peninsula, 27° 58' 47" S,
32° 25' 49" E. St Lucia Formation.
AGE. Campanian III.
Loc. 113. Cliff section at the SE corner of the Nibela Peninsula, 27° 58' 12" S, 32° 26' 57" E.
St Lucia Formation.
AGE. Campanian IV-V.
(v) The Southern Peninsula
Loc. 114. Foreshore exposures at the NW tip of the peninsula, 28° oo' 51" S, 32° 24' 44" E.
St Lucia Formation.
AGE. Campanian II.
Loc. 115. Foreshore exposures NW of Lake Pisechene, 28° 01' 03" S, 32° 25' 32" E. St
Lucia Formation.
AGE. Campanian III.
Loc. 116. Cliff section NE of Lake Pisechene, 28° 01' 06" E, 32° 26' 04" E. St Lucia Forma-
tion.
AGE. Campanian IV.
ZULULAND AND NATAL
297
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Loc. 117. Beach exposures at Hell's Gate, the extreme NE tip of the peninsula, 28° oo' 36" S,
32° 26' 48" E. St Lucia Formation.
AGE. Campanian IV.
(vi) Lake St Lucia
Locs 118-121. The Coves, and cliff sections for 2 km to the north and 3 km to the south,
eastern shores of the Southern Peninsula. St Lucia Formation.
Loc. 118. 28° oo' 58" S, 32° 26' 49" E. Loc. 120. 28° 03' 23" S, 32° 26' 27" E.
Loc. 119. 28° 02' 48" S, 32° 26' 47" E. Loc. 121. 28° 03' 57" S, 32° 26' 32* E.
AGE. Campanian III -IV.
Locs 122-125. Foreshore platforms 1200, 1600, 1900 and 2200 m north of Fanies Island Camp,
eastern shores of the Southern Peninsula. St Lucia Formation.
Loc. 122. 28° 05' 39" S, 32° 26' 22" E. Loc. 124. 28° 04' 57" S, 32° 26' 25" E.
Loc. 123. 28° 05' 19" S, 32° 26' 25" E. Loc. 125. 28° 04' 40" S, 32° 26' 30" E.
AGE. Campanian III-IV.
Loc. 126. Foreshore exposure 700 m south of the shore track leading south from Fanies
Island Camp, 28° 07' 27" S, 32° 25' 56" E. St Lucia Formation.
AGE. Maastrichtian II.
Loc. 127. Foreshore exposures 1-8 km south of Fanies Island Camp, 28° 07' 40" S, 32° 25' 56" E.
St Lucia Formation.
AGE. Maastrichtian.
Loc. 128. Cliff and foreshore exposures 2-7 km south of Fanies Island Camp, 28° 08' 02" S,
32° 25' 58" E. St Lucia Formation.
AGE. Maastrichtian III.
Locs 129, 130. Cliff and shore sections from 4-4 to 5-2 km south of Fanies Island Camp,
28° 08' 59* S, 32° 25' 47" E to 28° 09' 23" S, 32° 25' 41" E. St Lucia Formation.
AGE. Maastrichtian III.
Loc. 131. Low cliff and foreshore section 3-1 km north of Charter's Creek Rest Camp, 28°
09' 53" S, 32° 25' 37" E. St Lucia Formation.
AGE. Maastrichtian II.
Loc. 132. Degraded cliff and shore platform 300 m NE of the northern jetty at Charter's
Creek Rest Camp, 28° n' 32" S, 32° 25' 17" E. St Lucia Formation.
AGE. Maastrichtian I.
Loc. 133. Cliff section and beach platforms below Charter's Creek Rest Camp, 28° 12' 38" S,
32° 28' 08" E. St Lucia Formation.
AGE. Maastrichtian I.
Loc. 134. Cliffs and foreshore 1-2 km south of Charter's Creek Rest Camp, 28° 12' 59" S,
32° 25' 08" E. St Lucia Formation.
AGE. Maastrichtian I.
Loc. 135. Foreshore outcrops in Makakatana Bay, east of the village, 28° 13' 51" S, 32°
25' 08" E. St Lucia Formation.
AGE. Maastrichtian I.
J. THE MKUZE RIVER AND ITS TRIBUTARIES
North of Lake St Lucia, the coastal plain east of the Lebombo Mountains is covered by
Miocene to Pliocene marine sediments and Pleistocene to Recent dune sands. Exposures of the
Cretaceous are very poor, and are restricted to cliffs and pans along the Mkuze and its tributaries.
ZULULAND AND NATAL 299
Scattered exposures show Lebombo Volcanics overlain by conglomeratic Makatini Formation
with marine Upper Aptian fossils at the summit. Above the Aptian/Albian non-sequence,
Albian rocks are well exposed, and to the west there are isolated outcrops of Coniacian and
Santonian sediments.
(i) Southern part of Mkuze Game Reserve
Loc. 136. Banks of rivulet west of the road leading to the mine, 27° 44' 08" S, 32° 16' 50" E.
Makatini Formation.
AGE. Pre- Aptian ?
Loc. 137. Trackside exposures 1-5 km NNW of the old Msunduze drift along the road leading
to the mine, 27° 44' 25" S, 32° 16' 54" E. Makatini Formation.
AGE. Aptian ?
Loc. 138. Rivulet 800 m NE of the landing strip on Nxala Estate, 27° 43' 06* S, 32° 16' 38" E.
Makatini Formation.
AGE. Aptian IV.
Loc. 139. Roadside section and hillside on Nxala Estate 2-3 km NNE of Mt Nxala, 27°
41' 1 8" S, 32° 15' 30" E. Makatini Formation.
AGE. Aptian IV.
Loc. 140. Large working quarry south of road and west of Nsumu Pan, 27° 40' 16" S, 32°
15' 18" E. Makatini Formation.
AGE. Aptian IV.
Loc. 141. Hill slopes 750 m NNE of the previous locality. 27° 39' 52" S, 32° 15' 22" E.
Makatini Formation.
AGE. Aptian IV.
Loc. 142. Hillside east of track leading to the mine, 27° 44' 24" S, 32° 17' 12" E. Makatini
and Mzinene Formations.
AGE. Aptian IV ? ; Albian III.
Loc. 143. Small outcrops east of road by unnamed pan 3 km north of drift over Msunduze,
27° 43' 12" S, 32° 17' 20" E. Mzinene Formation.
AGE. Albian III.
Loc. 144. Low ridge on SW side of Nsumu Pan at mouth of unnamed northwards-flowing rivu-
let, 27° 41' 19" S, 32° 17' 50" E. Mzinene Formation.
AGE. Albian V.
(ii) The Morrisvale Area
Loc. 145. Degraded cliffs on the eastern side of the Msunduzi, 3 km SW of the farm Morrisvale,
north of Ngweni, 27° 42' 28" S, 32° 20' 56" E. St Lucia Formation. This locality extends for
several hundred metres, with a few metres of silts and concretions sporadically exposed in the
steep slopes between the flood plain and lowest terrace of the Msunduzi. The locality is of
great importance, for it represents one of the sections which van Hoepen (1926, 1929) and others
(e.g. Furon 1963) recognized as Turonian, and is said to be characterized by large oysters. In
fact, the Cretaceous sequence is capped by a basal conglomerate and limestone rubble of Miocene(?)
age, which yields the oysters, in turn capped by Pleistocene sands. The Cretaceous rocks are
poorly exposed, but loose boulders and excavations reveal richly fossiliferous horizons, crowded
with bivalves, both drifted and in life position. One level of concretions is crowded with
ammonites, especially Proplacenticeras , together with scarcer Yabeiceras, Forresteria, Peroniceras
and nautiloids.
AGE. Coniacian II.
27
300 CRETACEOUS FAUNAS
Loc. 146. Quarry 1-71 km NW of the farm Morrisvale, on the south bank of the Mkuze, east
of its junction with the Msunduzi, 27° 40' 36" S, 32° 22' 03" E. St Lucia Formation.
AGE. Santonian.
Loc. 147. Hill slopes in the Bantu area 4 km north of the confluence of the Mkuze and
Msunduze, north of Ngweni, 27° 38' 23" S, 32° 22' 22" E. St Lucia Formation.
AGE. Santonian.
(iii) Mantuma Rest Camp Area
Loc. 148. River cliff on west bank of Mkuze due east of Ndlelakufa Pan, 27° 34' 55" S, 32°
n' 50" E. Makatini Formation.
AGE. Aptian or pre-Aptian.
Loc. 149. Southern cliffs of Nhlohlela Pan, 2 km west of Mantuma Camp, 27° 35' 38" S,
32° 12' 05" E. Makatini Formation.
AGE. Aptian or pre-Aptian.
Loc. 150. Cliff section on southern side of Nhlohlela Pan, 1-3 km west of Mantuma Camp,
27° 35' 48" S, 32° 12' 28" E. Makatini Formation.
AGE. Aptian III-IV.
Loc. 151. Hill slopes on eastern side of Nhlohlela Pan, i km WNW of Mantuma Camp, 27°
35' 28" S, 32° 12' 53" E. Makatini Formation.
AGE. Aptian IV.
Loc. 152. Hill slopes south of road leading to Nhlohlela Pan from Denyer's Drift, 500 m west
of Mantuma Camp, 27° 35' 39" S, 32° 12' 53" E. Makatini and Mzinene Formations.
AGE. Aptian IV, Albian II-III.
Loc. 153. Site excavations for reservoir in Mantuma Camp, just east of Denyer's Drift, 27°
35' 36" S, 32° 13' 10" E. Mzinene Formation.
AGE. Albian III, IV ?
Loc. 154. Abandoned road metal quarry south of track 500 m east of Mantuma Camp, 27°
35' 33" S, 32° 13' 38" E. Mzinene Formation.
AGE. Albian III-IV ?
Loc. 155. Gully on south side of the Ndlamyane at Gujini, NE of the road leading NW from
Mantuma Camp, 27° 32' 54" S, 32° 10' 48" E. Makatini Formation.
AGE. Aptian.
Loc. 156. Bed of Ndlamyane, 600 m downstream from loc. 155, 27° 32' 42" S, 32° u' 20" E.
Mzinene Formation.
AGE. Albian III.
K. NORTHERN ZULULAND
This term covers the area from Jozini north to Ndumu, on the Mozambique border. In this
region, the crest of the Lebombos rises to more than 600 m, the volcanics dipping east at 2°-3°.
Dip slopes descend to the level of the coastal plain, with spurs extending eastwards into the
littoral, west of the Pongola..
The coastal plain itself has an average elevation of less than 100 m, rising to 180 m in the
Ndumu region. The Cretaceous succession has been truncated by a series of Tertiary trans-
gressions, the deposits of which, together with Pleistocene and Recent dune sands, mask the
whole area. Outcropping Cretaceous accounts for less than i per cent of the region. Sections
are thus confined to areas where streams and gullies draining west from the Lebombos to join
the Pongola cut through the Tertiary cover, and a few natural exposures and quarries, chiefly
ZULULAND AND NATAL 301
in the high ground around Ndumu. We have seen no exposures on the littoral, east of the
Pongola, nor have we been able to examine sections along the Usutu and in the Ndumu Game
Reserve.
(i) Mayezela Spruit
This is Myesa Spruit of Haughton (iQ36a : 285) ; there are exposures both east and west of
the drift on the dirt road from Jozini to Ndumu, 4-2 km NNE of the store at Otobotini.
To the west, platy rhyolites are well exposed, dipping in an easterly direction at about 10°.
The base of the Cretaceous is not visible, but on the high ground east of the crossing on the
northern branch, buff, coarse sandstones are well exposed.
Loc. 157. Gullies just east of the road, beyond the drift on the north branch of the Mayezela
Spruit, 10 km NE of Jozini, 27° 22' 45" S, 32° 06' 43" E. Makatini Formation.
AGE. Pre-Upper Aptian.
(ii) Mfongosi Spruit
Horizons from Lebombo Volcanics through conglomerates and up into marine Aptian and
Albian are exposed along this section, which lies 8 km NNE of Otobotini. A valuable account
and guide to this section is given by Haughton (i936a : 286), although it must be noted that the
present dirt track crosses the spruit 1-5 km east of the track shown by him (iQ36a : fig. 2).
Cretaceous sediments are exposed in the bed and walls of the deep gully cut by the Mfongosi,
and along degraded bluffs, capped by river gravels, both north and south of the present stream
bed.
Loc. 158. Cliffs on the north side of the north branch of the Mfongosi, 800 m NW of the drift
and 400 m from the junction with the main stream, 27° 21' 20" S, 32° 07' 18" E. Makatini
Formation.
AGE. Pre-Upper Aptian.
Loc. 159. Cliff on the south side of the Mfongosi, 100 m NW of the drift, 27° 21' 30" S, 32°
04' 25" E. Makatini Formation.
AGE. Pre-Upper Aptian.
Loc. 160. Cliff on south side of stream, at bend 400 m SE of the drift, 27° 21' 50" S, 32°
07' 45" E. Makatini Formation.
AGE. Pre-Upper Aptian.
Loc. 161. Sheer cliff at the bend of the stream 550 m east of the drift, 27° 21' 38" S, 32°
08' oo" E. Makatini Formation.
AGE. Pre-Upper Aptian.
Loc. 162. Cliff on south side of the stream 1200 m SE of the drift, 27° 21' 57" S, 32° 08' 15" E.
Makatini Formation.
AGE. Aptian.
Loc. 163. Cliff on the north side of the stream, just east of the old drift, 27° 21' 39" S, 32°
08' 30" E. Makatini Formation.
AGE. Haughton (ig36a : 288) records Acanthoplites spp. from this section, which thus appears
to be Aptian III.
Loc. 164. River cliff on the north side of the stream, 200 m NE of the old drift, 27° 21' 36" S,
32° 08' 32" E. Makatini Formation.
AGE. Aptian III.
Loc. 165. Cliff and cliff-top exposure on the south side of the stream 450 m SE of the old drift,
27° 21' 58" S, 32° 08' 43" E. Makatini Formation.
AGE. Aptian III.
302 CRETACEOUS FAUNAS
Locs 166, 167. Bluffs on the north side of the spur running eastwards from loc. 165, 27°
22' 02" S, 32° 08' 53" E to 27° 22' 04" S, 32° 09' 03" E. Makatini Formation.
AGE. Aptian III (loc. 166) ; Aptian III-IV (loc. 167).
Loc. 168. Bluffs along the ridge on the north side of the stream, 700-1200 m ESE of the old
drift, 27° 21' 43" S, 32° 09' 25" E (Fig. 10). Makatini Formation.
AGE. Aptian III-IV.
Loc. 169. Gully and adjacent hill slopes on the north side of the stream 2 km east of the old
drift, 27° 31' 38" S, 32° 09' 57" E (Fig. 10). Makatini and Mzinene Formations.
AGE. Aptian IV, Albian II, III.
(iii) Mlambongwenya Spruit
This stream section (Lombangwena Spruit of Haughton I936a : 292) lies 20 km NNE of the
Mfongosi sections. It is the most important section in Northern Zululand, for it provides the
only known exposures of fossiliferous Barremian marine sediments, previously unknown in
southern Africa. To the east, around Mlambongwenya Store, there are magnificent sections
across the Aptian-Albian boundary.
Loc. 170. Cliff and gully sections 2 km NW of the store, on the north side of the stream,
27° 10' 10" S, 32° 10' 13" E (Fig. n). Makatini Formation.
AGE. Barremian I-II, Aptian I-II.
Loc. 171. River cliff north of the stream, and hill slopes above, 250 m WSW of the store,
27° 10' 59" S, 32° u' 08" E. Makatini and Mzinene Formations.
AGE. Aptian IV, Albian II-III.
Loc. 172. Cliff section on the south side of the stream, 100 m west of the drift, 27° n' 37" S,
32° ii' 25" E. Makatini Formation.
AGE. Aptian IV.
Loc. 173. Steep cliff on the south side of the creek 300 m below the drift, 27° n' 37" S, 32°
n' 45" E. Makatini Formation.
AGE. Albian II-III.
Loc. 174. Shallow excavations and road sections extending from the store south towards the
drift, 27° n' 02" S, 32° n' 21" E. Mzinene Formation.
AGE. Albian III.
(iv) Ndumu
The occurrence of Cretaceous outcrops in the Ndumu region was known already to Anderson
(1907 : 61). The area was briefly described by Dietrich (1938), whilst Spath (1925) described a
Sharpeiceras which we believe to be from this area. Exposures occur along the north bank of
the Msunduzi, on hill slopes, south from Ndumu Store to the river, and around the police
station ; horizons from low in the Albian to the Lower Cenomanian are exposed (Fig. 12).
Loc. 175. Exposures in and around gully west of the track leading SW from Ndumu, in
Impala, 300 m south of Quotho Pan, 26° 56' 22" S, 32° 12' 48" E. Mzinene Formation.
AGE. Albian II-III.
Loc. 176. Slopes south of track and north of Quotho Pan across the boundary of Impala and
Wisteria 18122 locations, 26° 55' 59" S, 32° 18' 04" E. Mzinene Formation.
AGE. Albian III.
Loc. 177. Field along the north side of the Msunduzi Pan in Wisteria 18122 location, 2 km SW
of Ndumu Store, 26° 56' 08" S, 32° 13' 57" E. Mzinene Formation.
AGE. Albian IV-V.
LOCALITIES
183-185
LOCALITY
182
. 30
. 20
10m
10
LOCALITY
181
LOCALITY
179
LOCALITIES
178 and 180
LOCALITY
177
LOCALITIES
175 and 176
Yellow-weathering grey-buff silts
with courses of calcareous concretions.
Burrowed, with some cross-bedded
horizons. Silts with an in-situ
or little disturbed fauna alternate
with drifted shell -beds. Molluscs
abundant, including the following
ammonites: Mariella,- Hypoturrilites ,
Man tel 1 i ce ras , Forbes i ce ras
largi Iliertianum, Sharpeiceras
laticlavium, S. florencae.
Bivalves include Inpceramus,
Pterotrigonia, Gervillella and
Protocardia
Over 50m exposed
1m
6. Grey-buff, burrowed silts
ffe"^ 5 • Concretions crowded with
~f* Mariella s pp.
4. Grey-buff, burrowed silts
3. Concretions with abundant
Sharpeiceras and Mariella
2. Grey-buff, burrowed silts
1. Concretions with abundant
whole and fragmentary
Hamites and Anisoceras
Grey-buff silts with courses of calcareous concretions. Bioturbated, with some
cross-laminated horizons. Silts with an in-situ or little disturbed fauna
alternate with drifted shell-beds. Molluscs are abundant. Ammonites include
Mariella, Anisoceras , I di oh ami tes , Hami tes , Durnovari tes , Stoliczkaia, Hypengonoceras
Approximately 20m thick
Pebble Bed
Grey-buff burrowed and cross-laminated silts with calcareous concretions. Molluscs
common including ammonites Mortoniceras, Hysteroceras , Anisoceras , Myloceras ,
Labeceras , Puzosia
Seen to 15m
Silts with calcareous concretions. Horizons with abundant large Mortoniceras ,
Hysteroceras , Dipoloceras and heteromorphs occur above. Below, large Oxytropidoceras
occur. Thickness unknown
Silts with concretions-. Douvi lleiceras, Lyelliceras, Eubrancoceras , heteromorphs,
abundant bivalves. Thickness unknown
28
FIG. 12. The sequence around Ndumu, Iocs 175-185.
3o4 CRETACEOUS FAUNAS
Loc. 178. Sisal field north of Msunduzi Pan, on Ndumu A location, 1400 m SW of Ndumu
Store, 26° 56' 14* S, 32° 14' 25" E. Mzinene Formation.
AGE. Albian V-VI.
Loc. 179. Sisal fields north of the Msunduzi around the pumping station 2100 m SSW of Ndumu
Store, 26° 56' 28" S, 32° 14' 55" E. Mzinene Formation.
AGE. Albian V-VI.
Loc. 1 80. Concretions in the bed of the Msunduzi by the bridge 1-8 km SSE of Ndumu Store,
26° 56' 18" S, 32° 15' 25" E. Mzinene Formation.
AGE. Albian V.
Loc. 181. Hill slopes east of the road, i km SE of Ndumu Store, 26° 55' 51" S, 32° 18' 29" E.
Mzinene Formation.
AGE. Albian V, Cenomanian I-II.
Loc. 182. Ground surfaces over a radius of 300 m from Ndumu Store, 26° 55' 38" S, 32°
15' 13* E. Mzinene Formation.
AGE. Cenomanian II.
Loc. 183. Degraded quarry east of the road and 300 m SW of Ndumu police post, 26° 55' 10* S,
32° 15' 45" E. Mzinene Formation.
AGE. Cenomanian II.
Locs 184, 185. Hill slopes 600 m south and 500 m WSW of Ndumu police post, 26° 55' 28" S,
32° 15' 57" E and 26° 51" 18" S, 32° 16' 10" E. Mzinene Formation.
AGE. Cenomanian II.
Loc. 186. Makaane's Drift, 7-7 km south of Ndumu, 26° 59' 28" S, 32° 16' 13" E. Mzinene
Formation.
AGE. Albian VI.
VIII. DISCUSSION
The review and detailed description of sections given above outlines in broad
terms the history of eastern South Africa during the Cretaceous.
In Zululand, actual exposures account for less than i per cent of the area currently
shown on the i : 5 ooo ooo Carte Geologique d'Afrique (AGSA/UNESCO 1963). In
spite of this, we have been able to estimate a thickness of at least a kilometre for
the succession in the Mzinene- St Lucia region. The succession thickens markedly
north-eastwards, presumably towards the centre of the basin. The Lower Ceno-
manian, of the order of 10 m in thickness along the Mzinene, has thus thickened to
100 m at Ndumu. In the same direction, progressively lower marine horizons
appear, including previously unsuspected Upper Barremian sediments. Offshore,
we would infer that even lower marine horizons are present, and that there is a
continuous marine succession through the whole of the Cretaceous. The non-
sequences we have noted are thus probably features of the marginal areas of the
basin only, and borehole data suggest that marine sedimentation extended con-
tinuously into the Palaeocene.
A number of striking features of the succession are worthy of note at this point.
The bulk of the marine sequence consists of glauconitic silt-sand grade elastics ;
pure clays are rare. Conglomerates are confirmed to the basal parts of the sequence
ZULULAND AND NATAL 305
or to minor units associated with breaks in the succession. Throughout the sequence,
small-scale faunal/sedimentary cycles are conspicuous. These frequently take the
form of alternations of drifted shell-beds, and silts with an in situ fauna, or sequences
in which the sediment becomes finer in grade upwards. The base of each sequence is
crowded with pelletal glauconite and rests on a sharp sedimentary discontinuity.
Small-scale sedimentary structures are singularly lacking throughout much of the
sequence, especially the Mzinene and St Lucia Formations. This is due mainly to
intense biogenic reworking of the sediment. Diagnostic trace-fossils are rare, but
arthropod burrows (especially Thalassinoides) and Chondrites are abundant.
At several levels, high energy episodes disinterred early diagenetic concretions,
which were subsequently bored by lithodomous bivalves, and encrusted by oysters,
serpulids and other epizoans (Kennedy & Klinger 1972). These horizons are
present in the Aptian and Lower Albian, where they indicate minor breaks in sedi-
mentation. The 'hardground' at the Aptian/Albian boundary, however, is a palae-
ontologically detectable non-sequence and can be traced from Ndumu Spruit to
the Nyalazi River. The bored surfaces of the concretions below the Pterotrigonia
shepstoni conglomerate of Skoenberg represents part of Cenomanian, all Turonian
and some of Coniacian time.
Faunally, the Zululand Group is impressive. Our collection of ammonites is
fairly complete, but the few thousand bivalves and gastropods collected represent
only a fraction of the diverse fauna awaiting systematic and palaeoecological analysis.
Macroinvertebrate groups other than the Bivalvia, Gastropoda and Cephalopoda
form only a minority of the fauna. Belemnites occur in numbers only in the Aptian.
Echinoids are scarce save for a few levels in the Albian and Cenomanian. Brachio-
pods are common at only two levels in the Albian, although they range from Aptian
to Maastrichtian.
Ahermatypic corals are common only in the Cenomanian ; only one hermatype is
known, and is of Aptian age. Arthropods range throughout but (except cirripede
bores and ubiquitous burrows) are rare. Serpulids are frequent throughout ;
bryozoans less so. We have seen no macroscopic sponge remains.
Vertebrates are not common. Other than fish fragments (largely teeth) we have
noted occurrences of large reptilian remains only in the Lower Albian and the
Santonian-Lower Campanian. In contrast, plant remains are incredibly abundant
from the Barremian through to the Lower Campanian. Logs, up to several metres
long and 60 cm in diameter, are common at many levels, and in the Barremian -
Aptian there is a series of log beds. Lignite chips form an appreciable portion of the
sediment at many levels up into the Campanian.
Many of the above comments can also be applied to the Umzamba Formation
below and south of Durban. There, the bulk of the clastic material is sand-silt
sized, although a coarser glauconite fraction is more conspicuous than to the north.
Small-scale sedimentary rhythms are present and the sequence is bioturbated. The
fauna of the Umzamba Formation is far better documented than that of the Zulu-
land Series. It is predominantly molluscan ; we know of one coral, no brachiopods,
belemnites, nor macroscopic sponge remains. Echinoids are scarce, save at one
horizon ; arthropods (cirripede bores and burrows excepted) are absent. Serpulids
306 CRETACEOUS FAUNAS
and bryozoans range throughout. Wood, with logs several metres long, is abundant.
Lignite chips form an appreciable part of the sediment. Vertebrates are relatively
common at the base of the sequence ; Broom (1907) records a large mosasaur, a
plesiosaur and abundant chelonian debris. Woodward (1907) records elasmobranch
and teleost teeth.
IX. ACKNOWLEDGEMENTS
The visit to South Africa by one of us (W. J. K.) was made possible by a grant from
the Trustees of the Sir Henry Strakosch Bequest, which is gratefully acknowledged,
as is the assistance of the staff of the Union Corporation (Johannesburg), the Natal
Parks Board, and the South African Geological Survey. Mrs J. Hobday, Dr D.
Hobday, Professor L. C. King, Dr N. M. Savage, Mr J. Mcarthy, Mr M. Cooper and
Miss G. Lambert, all of Durban, assisted in many ways. Dr H. W. Ball, Dr M. K.
Howarth, Dr N. J. Morris, Mr D. Phillips, Mr R. J. Cleevely and Mr C. P. Nuttall
of the British Museum (Natural History) provided invaluable assistance in London.
We are both grateful to Mr P. J. Rossouw for his help and encouragement in ways
too numerous to mention, to Mr Johannes Nonyane for his help in the field, and to
the many farmers, land owners and others who rendered our fieldwork so profitable.
To the Director, South African Geological Survey, we are indebted for permission
to publish the data contained herein.
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KRIGE, L. J. 1932. The geology of Durban. Trans, geol. Soc. S. Afr., Johannesburg, 35 : 37-
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MONTANARO, E. & LANG, Z. 1937- Coelenterati, echinodermi, e brachiopodi del cretaceo
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310 CRETACEOUS FAUNAS
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pis 16-31.
J935- On a new species of Lysis (Gastropoda) from the Cretaceous of Pondoland. Rec.
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Cape Town, 31 : 277-391, pis 37-55.
ROGERS, A. W. & SCHWARZ, E. H. L. 1901. Report on parts of the Uitenhage and Port
Elizabeth Divisions. Rep. geol. Commn Cape Good Hope, Cape Town, 1900 (i) : 3-18.
1902. General survey of the rocks in the southern parts of the Transkei and Pondo-
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25-46.
RONIEWICZ, P. 1970. Borings and burrows in the Eocene littoral deposits of the Tatra Moun-
tains, Poland. Geol. J., Liverpool, Spec. Issue 3 : 439-446, 2 pis.
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Georgie, Tiflis, 1 : 165-273, pis 1-23.
SCHELPE, E. A. C. L. E. 1955. Osmundites natalensis — a new fossil fern from the Cretaceous
of Zululand. Ann. Mag. nat. Hist., London, (12) 8 : 652-656, pi. 17.
SELLWOOD, B. W. 1970. The relation of trace fossils to small scale sedimentary cycles in the
British Lias. Geol. J., Liverpool, Spec. Issue 3 : 489-504, i pi.
SERONIE- VIVIEN, M. 1959. Les localite's types du Se"nonien dans les environs de Cognac et
Barbezieux (Charente). In Colloque sur le Cr6tac6 Superieur Fran9ais. C. r. Congr. Socs
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SMITTER, Y. H. 1956. Foraminifera from the Upper Cretaceous beds occurring near the
Itongazi River, Natal. Palaeont. afr., Johannesburg, 3 : 103-107.
1957- Upper Cretaceous Foraminifera from Sandy Point, St Lucia Bay, Zululand. S. Afr.
J. Sci., Cape Town, 53 : 195-201.
ZULULAND AND NATAL 311
SOCIN, C. 1939. Gasteropodi e Lamellibranchi del Cretaceo medio-superiore dello Zululand.
Palaeontogr. ital., Pisa, 40 : 21-38, pis 5-6.
SORNAY, J. (Ed.) 1957. France, Belgique, Pays-Bas, Luxembourg. Cr6tace\ In Lexique
Stratigraphique International I (Europe), 4 a VI, 403 pp. CNRS, Paris.
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192 ib. On Upper Cretaceous Ammonoidea from Pondoland. Ann. Durban Mus.,
3 : 39-57. Pls 6, 7.
1922. On the Senonian ammonite fauna of Pondoland. Trans. R. Soc. S. Afr., Cape Town,
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1923-43. A monograph of the Ammonoidea of the Gault. Palaeontogr. Soc. (Monogr.),
London, 787 pp., 72 pis.
1925. On Upper Albian Ammonoidea from Portuguese East Africa. Ann. Transv. Mus.,
Pretoria, 11 : 179-216, 10 pis.
1953. The Upper Cretaceous Cephalopod fauna of Grahamland. Scient. Rep. Falkld
I si. Depend. Surv., London, 3 : 60 pp., 13 pis.
TATE, R. 1867. On some secondary fossils from South Africa. Q. Jlgeol. Soc. Land., 23 : 139-
174, pis 3-9.
VAN HOEPEN, E. C. N. 1920. Description of some Cretaceous ammonites from Pondoland.
Ann. Transv. Mus., Pretoria, 7 : 142-147, pis 24-26.
1921. Cretaceous Cephalopoda from Pondoland. Ibid. 8 : 1-48, pis i-n.
1926. Oor die Krytafsettinge van Soeloeland. 5. Afr. J. Sci., Cape Town, 23 : 216-222.
1929. Die Krytfauna van Soeloeland. I. Trigoniidae. Paleont. Navors. nas. Mus.
Bloemfontein, 1 : 1-38, pis 1-7.
1931- Die Krytfauna van Soeloeland. 2. Voorlopige Beskrywing van enige Soeloelandse
Ammoniete. i. Lophoceras, Rhytidoceras, Drepanoceras en Deiradoceras. Ibid. : 39-54,
14 figs.
1941. Die gekielde Ammoniete van die Suid-Afrikaanse Gault. I. Diploceratidae,
Cechenoceratidae en Drepanoceratidae. Ibid. : 55-90, figs 1-55, pis 8-19.
1942. Die gekielde Ammoniete van die Suid-Afrikaanse Gault. II. Drepanoceratidae,
Pervinquieridae, Arestoceratidae, Cainoceratidae. Ibid. : 91-157, figs. 56-173.
1944- Die gekielde Ammoniete van die Suid-Afrikaanse Gault. III. Pervinquieridae en
Brancoceratidae. Ibid. : 159-198, pis 20-26.
1946. Die gekielde Ammoniete van die Suid-Afrikaanse Gault. IV. Cechenoceratidae,
Dipoloceratidae, Drepanoceratidae, Arestoceratidae. [and] V. Monophyletism or poly-
phyletism in connection with the ammonites of the South African Gault. Ibid. : 199-271,
figs. 174-268.
I95ia. Die gekielde Ammoniete van die Suid-Afrikaanse Gault. VI. The so-called old
mouth-edges of the ammonite shell. Ibid. : 273-284, figs 269-287.
I95ib. Die gekielde Ammoniete van die Suid-Afrikaanse Gault. VII. Pervinquieridae,
Arestoceratidae, Cainoceratidae. Ibid. : 285-344, figs 288-442.
19510. A remarkable desmoceratid from the South African Albian. Ibid. : 345-349,
3 figs.
I955a. New and little-known ammonites from the Albian of Zululand. S. Afr. J. Sci.,
Cape Town, 51 : 355-377, figs 1-31.
I955b. A new family of keeled ammonites from the Albian of Zululand. Ibid. : 377-382,
figs 32-36.
1963. An Albian astacurid from Zululand. Ann. geol. Surv. Pretoria, 1 : 253-255.
ig66a. New and little known Zululand and Pondoland ammonites. Ann. geol. Surv.
Pretoria, 4 : 158-172, 12 pis.
I966b. New ammonites from Zululand. Ibid. : 183-186, 7 pis.
I966c. The Peroniceratidae and allied forms of Zululand. Mem. geol. Surv. Rep. S. Afr.,
Pretoria, 55 : 70 pp., 27 pis.
312
CRETACEOUS FAUNAS
VENZO, S. 1936. Cefalopodi del Cretacea medio-superiore dello Zululand. Palaeontogr. ital.,
Pisa, 36 : 59-133. pis 5-™-
WIEDMANN, J. 1959. La Cre'tace' superieur de 1'Espagne et du Portugal et ses ce"phalopodes.
In Colloque sur le Cr6tac6 Superieur Fransais. C. r. Congr. Socs sav. Paris Sect. Sci. (Dijon),
1959 : 709-764, 7 pis.
1964. Le Cr6tace" supe'rieur de 1'Espagne et du Portugal et ses Cephalopodes. Estudios
geol. Inst. geol. Lucas Mallada, Madrid, 1964 : 107-148, 39 figs.
WOODS, H. 1906. The Cretaceous fauna of Pondoland. Ann. S. Afr. Mus., Cape Town,
4 : 275-350, pis 33-44-
WOODWARD, A. S. 1907. Notes on some Cretaceous fish teeth from the mouth of the Um-
penyati River, Natal. Rep. geol. Surv. Natal Zululand, Pietermaritzburg, 3 : 99-101,
pi. 10 (pars).
WRIGHT, C. W. 1957. Mollusca 4. Cephalopoda, Ammonoidea. In Moore, R. C. (Ed.),
Treatise on Invertebrate Paleontology, L. xxii + 4OO pp. Lawrence, Kansas.
XI. INDEX
The page numbers of the principal references are printed in bold type; an asterisk (*) denotes a figure.
Text-figs. 2 and 3 follow p. 280; text-figs. 10 and n follow p. 300.
Acanthoceras 277, 291
cornigerum 277
crassiornatum 277
flexuosum 277
hippocastanum Crick non Sow.
277
latum 277
munitum 277
quadratum 277
robustum 277
Acanthoplites 275, 301, fig. 10
Acompsoceras 276
Aconeceratidae 274, fig. n
'Acrioceras' 274, fig. n
Albian, 266-73, 275-6
Allocrioceras spp. 278
alluvium, Recent fig. 3
Amatis farm 285
ammonites 269-70, 273
faunas 266, 271
Ammonoceratites 276
Anagaudryceras 276, 286
sacya 276
Anapachydiscus arialoorensis 280
subdulmensis 280
wittekindi 280
Ancyloceras 275, fig. n
sp. 274
Ancyloceratidae 274-5, fig. n
Anderson, W. 270-1, 289
' Andersonites' listeri 279
Androiavites 276
Angles section (Basses-Alpes)
274
Anisoceras 276-7, 290, 303
Aptian 266-7, 270-3, 274-5
boundary with Barremian 274
Arcidae 287
Arestoceras 276
Arialoor Group (S. India) 270
arthropods 305
burrows 287, 290, 305
Askoloboceras 276
Australiceras 275, fig. n
Australietta 280
australis 280
besairei 280
Avellana 290
Baculites 279-80, 283, 291, 293,
297
bailyi 278-9
capensis group 279
sulcatus 280, 282
vagina Van Hoepeni 280
Bailey. W. H. 269
Bantu Reserve No. 3 284
Barremian 266-7, 2^9- 272>
273-4
boundary with Aptian 274
Barroisiceras 278
haberfellneri zone 278
onilahyense zone 278
umzambiensis 270, 281
basement rocks 266, 269, fig. 3,
282
Basseoceras krameri 278
' Beaudanticeras' 276
Behavites 280
belemnites fig. n, 305
Belvedere farm 288
Bhimaites 276-7
bilharzia 285
bivalves 266, 269, 282, 286-7,
290-1, 293, 297, 299, figs,
lo-n, 303, 305; see also
Inoceramus, Ostreidae, etc.
Borissiakoceras 277
Bostrychoceras 280-1
indicum 278, 287
sp. 280
brachiopods 266, 271, 305
British Museum (Natural His-
tory) 266, 306
bryozoans 266, 305-6
burrows, 293, 297; see also arth-
ropods
Baboon's Krans 285
Cain Railway Bridge 283
Cainoceras 276
Calycoceras 291
choffati group 277, 287, 291
gentoni paucinodatum 277
laticostatum 277
naviculare group 277
newboldi newboldi 277
planecostata 277
spinosum 277
nitidum 277, 291
Campanian 266, 269-73, 280-1
Cechenoceras 276
Cekeni Estate 284
Cenomanian 266, 268-73, 276-7
Cercomya 290
Charter's Creek 284, 298
Chelmsford farm 283
chelonians 306
Cheloniceras 275, fig. n
gottschei 275
aff. proteus 275
spp. fig. ii
Cheloniceratidae 274
Chlamys 290
Chondrites 305
cidarid spines 282
cirripede bores 305
'Clansayes' horizon 275
'Cleoniceras' 276
Cognac 278
Colchidites 274, fig. 11
Collignonceratidae 270
Coniacian 266, 268-73, 278-9
corals 266, 305
Corbieres 279
Coves, the 298
Craie de Villedieu 278
Crassatella 290
Crick, G. C. 266, 289
Crioceratidae 274
' Crioceratites' fig. n
crocodiles 285
Cyclorisma 290
Cyclothyris 290
Damesites fig. 10
? sp. nov. 276
Deiradoceras 276
Denyer's Drift 300
Deshayesitidae 274
Desmoceras 276-7, 290
latidorsatum 277
Desmoceratidae 275-7
Diadochoceras 275, fig. 10
nodostocatum 275
Diaziceras tissotiaeforme 283
Die Rooiwalle 292
Diplacmoceras bidorsatum zone,
280
Diplasioceras 276
Diploceras [sic] 286; see Dipo-
loceras
Diplomoceratidae 279-80, 283,
293
Dipoloceras (Diplasioceras) 276
(Dipoloceras) 276, 286, 303
Douvilleiceras 275-6, fig. 10, 303
mammillatum 275
orbignyi 275
Durban 266-7, 269-70, 282, 305
Museum 267
University Collection 267
Durnovarites 276, 290, 303
du Toit, A. L. 270
echinoids 266, 305
' Eedenoceras' multicostatum 278
'Emericeras' 274, fig. n
Empangeni 282
Enseleni Reserve 267
Entolium 286
' Epiphylloceras' 281
epizoans 305
Erioliceras 276
Etheridge, R. 266
Eubaculites 281
ootacodensis 281
Eubrancoceras 303
aff. aegoceratoides 276
Eucalycoceras 277
Eupachydiscus 280
isculensis zone 279
? sp. 279-80
Euspectoceras 276
Eutrephoceras 297
Eutyloceras fig. n
phestum 274
Exogyra 286, fig. u
False Bay 268, 271, 273, fig. 3,
292-8
'Falsebayites' peregrinus 279
Panics Island Camp 298
INDEX
fish teeth 305-6
' ' Fluminites' albus 279
Foraminiferida 271
Forbesiceras largilliertianum 277,
3°3
sculptum 277
Forresteria 283, 299
alluaudi 278, 282
hammer sleyi 278
itwebae 278
razafiniparyi 278
reymenti 278
vandenbergi 278
Fraudatoroceras besairei 278
Fynn, H. F. 269
Garden, R. J. 269
gastropods 266, 282, 287, 290,
297, fig. 10
Gaudryceras 276
spp. 279-80
Gauthiericeras ? 279
Geological Survey of South
Africa 266
Gervillella 286, figs. 10-11, 303
Glenpark Estate 284
Glycymeris 286-7
Goniomya 286, 290
Grand Champagne 280
Graysonites 276
Gujini 300
Gunnarites antarticus 280
Gyrodes 290
Haig Halt 282-3
Hamites 276, 286, 303
Hauericeras 280, 293
gardeni 279-81
Haughton, S. H. 266, 301
Hell's Gate 296, 298
Hemiaster 286-7
Hemihoplitidae 274, fig. n
Heteroceras 274, fig. n
heterodont bivalves 286-7, 297>
figs. lo-n
heteromorph ammonites 275,
fig. 10, 303
Hluhluwe 267-8, fig. 3, 283-4,
285, 288, 292, 294-6
River fig. 3, 284, 292, 294-5
' Hluhluweoceras' fugitivum 279
Hoplitidae, boreal 275
Hoplitoplacenticeras plasticum*
280
Hoploscaphites 281
Hypengonoceras 276, 303
Hyphantoceras 280
reussianum 278
sp. 279
Hypophylloceras 276-7, 286
velledae 276
Hypoturrilites 276-7, 290-1, 303
carcitanensis 277
gravesianus 277
nodiferus 277
tuber culatus 277
Hysteroceras 276, 286, 303
313
Idiohamites 276, 303
Impala 302
Indabana 288
Ingwavuma River 270
Inoceramidae 270, 273, 281, 293,
297; plate, fig. 2
Inoceramus 269, 286, 303
expansus 281
labiatus zone 278
Insleep 292
International Geological Con-
gress, 1929 270-1
Iswelihle 288
Itongazi River 266-7, 270
Itweba Beds 272
Izindhluzabalungu Deposits 269
Izwehelia farm 288-9
Jozini 300-1
Karapadites ? sp. 279
Karoo formation 283
Komeceras 276
Kossmaticeras 279
sakondryense 278
sparcicosta 278
theobaldianum 278; zone 278
(Natalitd) 282
Kossmaticeratidae 283
Kwa Mbonambi fig. 3, 282
Labeceras 276, 286, 303
Labeceratidae 286
Lake View 282
Lebombo Mountains 271, 298,
300
Volcanics 267, 273, 283, 285,
299-301
Lechites 276
Le Mans 276
Lewesiceras australe 278
spp. 278
Leymeriella tardefurcata zone 275
Linotrigonia 290
Lister's Point 292, 294
lithodomous bivalves 305
Lithophaga 287, fig. 10
lithostratigraphic terminology
272
locality details 281-304
logS 286-7, 293, figS. 10-11,
305-6; see trees, fossil
Lombangwena Spruit 302
Lophoceras 276
Lyelliceras 276, 303
lyelli 276
pseudolyelli 276
Lytoceras 275
Lytoceratidae 275, fig. 10
Maastrichtian 266, 268-73, 281
Madagascar 275, 278
Mains Farm 282
Makaane's Drift 304
Makakatana Bay 298
Makatini Formation 266, 272,
273, fig. 3, 282, 285, 288,
299-302; plate, fig. i
Mammites nodosoides zone 278
INDEX
Mantelliceras 276-7, 290-1, 303
cantianum group 277
indianense 277
mantelli zone 276
patens 277
spissum 277
Mantelliceratinae 276
Mantuma Rest Camp area 300
Manuan 267, 288; see Muny-
wana
Manuaniceras 276
Maorites sp. 280
Margarites 286
Marietta 276-7, 290-1, 303
oehlerti 277, 290
spp. 277, 290
martimpreyi zone 276
Mason's Camp 294
Maydon Wharf 282
Mayezela Spruit 301
Megacucullaea fig. n
Megatrigonia fig. n
shell bed plate, fig. i
Menabites 280, 297
australis 280
besairei 280
(Australiella) 280
Menuites 281
Mfekayi Halt 284
Mfolozi River 266-8, 270, fig. 3,
282-3
Mfomoto farm 292
Mfongosi River 301
Spruit 273, 301-2, fig. 10
Mfuthululu, Lake 283
Mhlangamkulu River 282
microfloras 272
Miotexanites 279
Mkuze Game Reserve 299
River 271, 292, fig. 3, 298-300
Mlambongwenja River 273
Mlambongwenya Spruit 302, fig.
ii
Modiolus 286, 290
Mojsisovicsia 276, 286
molluscs 271, 282, 286-7, 290-1,
293, figs. 10-11, 303, 305;
see also bivalves, gastro-
pods, ammonites, etc.
Monte Rosa 285
Monzi 269, 271, 282-3
Monoval 284
Morrisvale area 299-300
Mortoniceras (Mortoniceras) 276,
286, 303
umkwelanense 270
(Deiradoceras) 276
(Durnovarites) 276
Mortoniceratidae 276, 286
mosasaur 306
Mozambique 266-7, 27°
Mpenjati River 266-7, 270, 282
Msunduzi drift 299
pan 304
River 271, 283, 299-300, 302,
304
Mtubatuba 267, 282-3
Muniericeras lapparenti 279
Munyuana Beds 272; see Muny-
wana
Munywana 267, 271, 288, 289,
292
Myesa Spruit 301; see Mayezela
Spruit
Myloceras 276, 286, 303
Mzinene Formation 266, 272,
273, fig. 3, 284-5, 288-9,
299-300, 302, 304-5
River 267-73, fig. 3, 285, 292,
304; plate, fig. i
lower reaches 292
upper reaches 285-8
Narrows, the 292
Natal 272; see Pondoland
Natalita 282
National Museum, Bloemfontein
267
nautiloids 266, 286, 297, 299
Ncedomhlope farm 295
Ndabana 285
Beds 272
Ndlamyane River 300
Ndlelakufa Pan 300
Ndumu 267, 300-1, 302-4
Spruit 305
Neithea 286-7, 29°
Neitheidae 293
Neogaudryceras sp. 280
'Neosilesites'
Newton, R. B. 266
Ngweni 285, 299-300
Nhlohlela Pan 300
Nibela peninsula 292, 296, 297*
Nkundusi 295
Nostoceras ? sp. 280
Nsumu Pan 299
Nxala Estate, Mt Nxala 299
Nyalazi River 268, fig. 3, 283-4,
292, 295-6, 305
trading store 284
Nyokaneni River 282
Onderdeel farm 292
Ostlingoceras 277, 290-1
rorayensis 277
Ostreidae 271, 282, 286, 297,
299, figs. lo-n, 305
Otobotini 301
Oxytropidoceras 276, 286, 303
(Androiavites) 276
(Manuaniceras) 276
(Oxytropidoceras) 276
(Tarfayites) 276
oysters, see Ostreidae
Pachydesmoceras denisonianum
278, 287
sp. 278, 287
Pachydiscidae 280-1, 297
Pachydiscus manambolensis 280
neubergicus zone 281
(Neodesmoceras) sp. 280-1
(Pachydiscus) 280
Palaeocene 272
Panopea 290, fig. n
Panplaas farm 295
Parabehavites serratomarginatus
279
Paratexanites (Paratexanites) 279
Pasina 283
Peaston North Bank Drain 283
Pectinidae 297
Peroniceras 278, 282—3, 299
besairei 278
dravidicum zone 278
tenuis 278
tridorsatum group 278
(Zuluiceras) charlei 278
(Zuluites) 279
Peroniceras Beds 272, 294
Peroniceratidae 279
Perrisoptera 290
Petinoceras 276
Pholadomya 286, 290
vignesi 286, 290
Phylloceras 274-5, fig. n
serum 274, fig. n
(Hypophylloceras) 276-7, 286
velledae 276
Picnic Point 294
Pinna 290, 297
Pisechene, Lake 296
Placenticeras 279
syrtale zone 279
plant remains, see logs
Pleistocene sands fig. 3
plesiosaur 306
Plesiotexanites stangeri 279-80
Pleuromya 287, fig. 10
Pondoland 270, 273, 281-2
Pongola River 270-2, 300-1
Praemuniericeras ? sp. 279
Pretoria University Collection
267
Protocheloniceras 274-5, fig. n
albrechtiaustriae 274
Proplacenticeras 283, 287, 291,
299
kaffrarium 278, 283, 287
subkaffrarium 278, 287
umkwelanense 278, 282, 287
Protanisoceras 275, fig. 10
Protexanites (Miotexanites) 279
(Protexanites) 279
Protocardia 286, 303
Pseudhelicoceras 276, 286
Pseudohaploceras 275
matheroni 274
Pseudophyllites indra 279
Pseudoschloenbachia 280, 293
primitiva 279
umbulazi 281-2
sp. 279
Pseudothurmannia anguhcostata
zone 274
Pseudoxybeloceras matsumotoi
278
Pterotrigonia 286-7, 29° nS- IO»
303
shepstonei 287, 291
conglomerate 287, 289, 291,
305
Puzosia 276-7, 286, 303
spp. 278
Puzosiidae 276, 283
Pycnodonte 297
Quotho Pan 302
reptiles 305-6
research, history of 269-72
Rhytidoceras 276
Richards Bay 267, fig. 3
Ricnoceras 276
Riverview 268, 282
sugar mill 283
Rossalites 276
Russia, S., Barremian sequence
in 274
Saghalinites 281
cala 280
St Lucia area 267, 268*, 270, 272,
304
Game Reserve 295
(Lake) 268, 271, 273, fig. 3,
292-8; plate, fig. 2
St Lucia Formation 266, 272,
273, fig. 3, 282-5, 288-9,
292, 294-6, 298-300, 305;
plate, fig. 2
Saintes, Aquitaine 279
Sanmartinoceras 274, fig. n
Santonian 266, 269-72, 279-80
Sarthe 276
Scaphites (Scaphites) 277, 279,
290
meslei 278
cf. simplex 277
spp. 277-8, 283
Scaphitidae 282
Schloenbachia 276
Sciponoceras 277, 290
roto 277, 290
Senonian 269-72, 289; see also
Coniacian, etc.
serpulids fig. 10, 305-6
Sharpe, Daniel 266
Sharpeiceras 276-7, 290-1, 302-3
falloti 277
florencae 277, 303
laticlavium 277, 303
spp. 290
Shire Estate 283
Sibayi, Lake 272
Skoenberg, the 288-92, 305
INDEX
Beds 272, 289
region 285, 288-91
Sometsu Road 282
'Sonneratia' 276
South African Museum, Cape
Town 267
Southern peninsula, Lake St
Lucia 292, 296-8
Spatangidae 297
Spath, L. F. 266
sponges 305
Sphenoceramus 282
Sphenotrigonia fig. 10
stage limits and subdivisions,
273-81
Steinmanella henningi fig. n
Stoliczkaia 276, 290, 303
africana 276
dispar zone 268
dorsetensis 276
notha 276
Stomohamites 277, 290
Stormberg Basalts 266, 269
stratigraphic nomenclature 272-
273
synthesis 267-9
Submortoniceras 280, 293
woodsi 280
sp. 293
Subprionotropis cricki 270, 281;
horizon of 279
Table Mountain Sandstone 266,
269
Tarfayites 276, 286
Terasceras 276
Teredo figs. 10-11
Tertiary sands and limestones
fig. 3
Tetragonites 276
subtimotheanus 277
Texanites 279, 293
oliveti 279
soutoni 280-1
texanus zone 279
spp. 280
(Plesiotexanites) stangeri 280-1
densicosta 279
sparcicosta 279
Texanitidae 278, 293
Teza, Lake 282
Thalassinoides 305; see arthro-
pod burrows
Tissotia 278
315
Tonohamites 275
Trafalgar Beach 282
Transkei 268*, 269; see Um-
zamba River
Transvaal Museum 267
trees, fossil 269; see logs
Trichinopoly Group (S. India)
270
Trigoniidae 286, figs. 10-11
Tropaeum 275, figs. 10-11
sp. 274
Turonian 266, 268-72, 277-8
Turrilites 291
acutus 277
co status 277
scheuchzerianus 277
Umkandandhlouvu River 270
Umkwelane Hill 267-70, 282-3
Umlatuzi Lagoon 270
Umsinene 267
Beds 272, 276
Umtamvuna (Umtamfuna) Cre-
taceous 269
River 269
Umzamba Formation, Beds 266,
269-72, 273, 281-2, 305
River 267, 268*, 273, 281
Umzigi 292
Utsutu River 301
Utaturiceras 276
Valdedorsella 275, fig. n
van Hoepen, E. C. N. 266, 289,
294
Veneridae 286-7
Veniella 286, fig. 10
vertebrates 305-6
Wisteria 302
wood, fossil, see logs
Yabeiceras 299
spp. 278
Zulu names 267
Zuluiceras charlei 278
Zuluites 279
Zululand 266-306 passim, 268*;
see also Pondoland
general locality map fig. 2
Group 266, 272-3, 305
W. J. KENNEDY
Dept of Geology <&- Mineralogy
PARKS ROAD
UNIVERSITY OF OXFORD
ENGLAND
H. C. KLINGER
GEOLOGICAL SURVEY OF SOUTH AFRICA
PRIVATE BAG Xii2
PRETORIA oooi
REPUBLIC OF SOUTH AFRICA
Accepted for publication 14 January 1974.
PLATE
FIG. i. Megatrigonia shell bed, Makatini Formation (Aptian), loc. 39, Mzinene River,
Zululand. Hammer-head is 15 cm long. (p. 285).
FIG. 2. Inoceramid fragments in Maastrichtian silts, St Lucia Formation, SE shores of Lake
St Lucia, Zululand. Hammer-head is 15 cm long. (p. 298).
Bull. Er. Mus. nat. Hist. (Geol.) 25, 4
A LIST OF SUPPLEMENTS
TO THE GEOLOGICAL SERIES
OF THE BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
1. Cox, L. R. Jurassic Bivalvia and Gastropoda from Tanganyika and Kenya.
Pp. 213 ; 30 Plates ; 2 Text-figures. 1965. OUT OF PRINT.
2. EL-NAGGAR, Z. R. Stratigraphy and Planktonic Foraminifera of the Upper
Cretaceous — Lower Tertiary Succession in the Esna-Idfu Region, Nile Valley,
Egypt, U.A.R. Pp. 291 ; 23 Plates ; 18 Text-figures. 1966. £11.
3. DAVEY, R. J., DOWNIE, C., SARJEANT, W. A. S. & WILLIAMS, G. L. Studies on
Mesozoic and Cainozoic Dinoflagellate Cysts. Pp. 248 ; 28 Plates ; 64 Text-
figures. 1966. £8.20.
3. APPENDIX. DAVEY, R. J., DOWNIE, C., SARJEANT, W. A. S. & WILLIAMS, G. L.
Appendix to Studies on Mesozoic and Cainozoic Dinoflagellate Cysts. Pp. 24.
1969. 95p.
4. ELLIOTT, G. F. Permian to Palaeocene Calcareous Algae (Dasycladaceae) of
the Middle East. Pp. in ; 24 Plates ; 16 Text-figures. 1968. £6.10.
5. RHODES, F. H. T., AUSTIN, R. L. & DRUCE, E. C. British Avonian (Carboni-
ferous) Conodont faunas, and their value in local and continental correlation.
Pp- 3*3 > 31 Plates ; 92 Text-figures. 1969. £13.10.
6. CHILDS, A. Upper Jurassic Rhynchonellid Brachiopods from Northwestern
Europe. Pp. 119 ; 12 Plates ; 40 Text-figures. 1969. £5.25.
7. GOODY, P. C. The relationships of certain Upper Cretaceous Teleosts with
special reference to the Myctophoids. Pp. 255 ; 102 Text-figures. 1969.
£7-7°-
8. OWEN, H. G. Middle Albian Stratigraphy in the Anglo-Paris Basin. Pp. 164 ;
3 Plates ; 52 Text-figures. 1971. £7.20.
9. SIDDIQUI, Q. A. Early Tertiary Ostracoda of the family Trachyleberididae
from West Pakistan. Pp. 98 ; 42 Plates ; 7 Text-figures. 1971. £9.60.
10. FOREY, P. L. A revision of the elopiform fishes, fossil and Recent. Pp. 222 ;
92 Text-figures. 1973. £11.35.
11. WILLIAMS, A. Ordovician Brachiopoda from the Shelve District, Shropshire.
Pp. 163; 28 Plates; n Text-figures; no Tables 1974. £12.80.
Printed in Great Britain by John Wright and Sons Ltd. at The Stonebridge Press, Bristol BS4 jNU
A REVISION OF SAHNI'S TYPES
OF THE BRACHIOPOD SUBFAMILY '
CARNEITHYRIDINAE
U. ASGAARD
BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
GEOLOGY Vol. 25 No. 5
LONDON: 1975
A REVISION OF S ARM'S TYPES OF THE
BRACHIOPOD SUBFAMILY CARNEITHYRIDINAfi
Institut for historisk Geologi og Palaeontologi
0stervoldgade Kobenhavn Denmark
Pp. 317-365 ; 8 Plates ; 14 Text-figures ; 5 Tables
BULLETIN OF
THE BRITISH MUSEUM (NATURAL HISTORY)
GEOLOGY Vol. 25 No. 5
LONDON: 1975
THE BULLETIN OF THE BRITISH MUSEUM
(NATURAL HISTORY), instituted in 1949, is
issued in five series corresponding to the Departments
of the Museum, and an Historical series.
Parts will appear at irregular intervals as they
become ready. Volumes will contain about three or
four hundred pages, and will not necessarily be
completed within one calendar year.
In 1965 a separate supplementary series of longer
papers was instituted, numbered serially for each
Department.
This paper is Vol. 25, No. 5, of the Geological
(Palaeontological) series. The abbreviated titles of
periodicals cited follow those of the World List of
Scientific Periodicals.
World List abbreviation :
Bull. Br. Mus. nat. Hist. (Geol.)
ISSN 0007-1471
Trustees of the British Museum (Natural History), 1975
TRUSTEES OF
THE BRITISH MUSEUM (NATURAL HISTORY)
Issued 19 May, 1975 Price £4.50
A REVISION OF S ARM'S TYPES OF THE
BRACHIOPOD SUBFAMILY CARNEITHYRIDINAE
By ULLA ASGAARD
CONTENTS
Page
SYNOPSIS .......... 320
I. INTRODUCTION ......... 320
II. ACKNOWLEDGEMENTS ........ 320
III. HISTORICAL REVIEW . . . . . . . . 321
IV. THE PROVENANCE OF THE TYPE MATERIAL ..... 323
V. REVIEW OF SAHNI'S MATERIAL OF CARNEITHYRIDINES . . 325
Carneithyris carnea (J. Sowerby, 1812) .... 326
C. elongata (J. de C. Sowerby, 1823) ..... 327
C. subpentagonalis Sahni, 1925 ...... 327
C. circularis Sahni, 1925 ....... 328
C. variabilis Sahni, 1925 ....... 328
C. acuminata Sahni, 1925 ...... 329
C. norvicensis Sahni, 1925 ...... 329
C. subovalis Sahni, ig25a ....... 330
C. uniplicata Sahni, I925a ...... 330
C. daviesi Sahni, I925a ....... 331
C. ornata Sahni, 1929 . . . . . . 331
Pulchrithyris gracilis Sahni, 1925 ..... 332
P. extensa Sahni, 1925 ....... 333
Magnithyris magna Sahni, 1925 ...... 333
M. truncata Sahni, 1929 ....... 334
Piarothyris rotunda Sahni, 1925 ...... 334
Ellipsothyris similis Sahni, 1925 ..... 334
Ornithothyris carinata Sahni, 1925 ..... 335
Chatwinothyris subcardinalis Sahni, 1925 .... 335
Ch. symphytica Sahni, 1925 ...... 336
Ch. curiosa Sahni, ig25a ....... 337
Ch. gibbosa Sahni, I925a ....... 338
VI. DISCUSSION .......... 338
Material .......... 339
The phylogenetic tree of Sahni (i925a) .... 339
Morphology of the cardinalia . . . . . . 341
External morphology ....... 343
Statistical analyses ........ 345
Conclusions ......... 359
VII. CONCLUDING REMARKS ........ 360
VIII. REFERENCES .......... 361
IX. INDEX . 362
320 SAHNI'S TYPES
SYNOPSIS
Sahni's type material of Upper Campanian and Lower Maastrichtian carneithyridine brachio-
pods is reviewed and the type specimens refigured. The present material of carneithyridines in
English collections is discussed. It is concluded that only one genus, Carneithyris, is present
and is represented by two species, Carneithyris carnea from the Upper Campanian and Carnei-
thyris subcardinalis from the Lower Maastrichtian. The stratigraphical variation of the
genus, its palaeoecology and relationship to different facies are examined.
I. INTRODUCTION
THE Upper Campanian and Lower Maastrichtian terebratulids, formerly known under
the names Terebratula carnea J. Sowerby (1812) and T. elongata J. de C. Sowerby
(1823), were split up by Sahni (1925, iQ25a, 1929) into seven genera represented by
22 species. In the course of work on Maastrichtian and Danian carneithyridine
terebratulid material from Denmark (Asgaard 1963) I found it necessary to study
the types of Sahni, and this led to many visits to the English museums housing the
types and to field work in the Norwich area in the years 1962 to 1972. This paper is
a result of these investigations. A review of the types is followed by a discussion of
the validity of the genera and species. It was found that Sahni's types have
suffered much wear since they were figured.
The possibility that seven closely related genera represented by 22 species could
have existed in the same area within the relatively short time-span covering the
Upper Campanian and Lower Maastrichtian cannot be excluded. However, it can
be shown that the premises on which these genera and species were founded are not
tenable and that the phylogenetic tree created by Sahni (i925a) does not have a firm
stratigraphical footing.
The conclusion of this paper is that the English material represents only one genus
with two species, viz. Carneithyris carnea (J. Sowerby 1812) from the Upper Campan-
ian and Carneithyris subcardinalis (Sahni 1925) from the Maastrichtian. The
geographical and stratigraphical variation of these species is described. An attempt
was made to demonstrate the variation statistically but this was not found to be
possible with the present material.
The representatives of Carneithyris treated here are chiefly from the white chalk
facies of Campanian and Maastrichtian age. However, the discussion is supple-
mented by reference to forms from other facies of the Upper Cretaceous and Lower
Tertiary where these can shed light on the variation and phylogeny of the genus.
II. ACKNOWLEDGEMENTS
My sincere thanks are due to the following institutions and persons : Mr Ellis F.
Owen of the British Museum (Natural History), Dr Brian Me Williams of the Norwich
Castle Museum, and Mr Christopher J. Wood of the Institute of Geological Sciences,
London. To Mr C. J. Wood and Mr Norman B. Peake of Norwich I am deeply
indebted for valuable discussions on the stratigraphy of Norfolk and guidance in
the field. Mr Walter Kegel Christensen of the Mineralogisk Museum, Copenhagen,
kindly gave advice on statistical methods. I am grateful to Dr Finn Surlyk for many
OF CARNEITHYRIDINAE 321
constructive discussions on brachiopods and their ecology, and to the late Professor
Alfred Rosenkrantz who encouraged me to take up the study of the Carneithyris
group. The text-figures are the work of Mr H. Egelund. Last but not least my
thanks are due to Dr Richard G. Bromley who patiently took the many photographs
of the types, often under trying conditions, and later, assisted by Dr John S. Peel,
improved the English of the manuscript. My final visit to England for study in
1972 was supported by the Danish Science Council and the Royal Society of London.
III. HISTORICAL REVIEW
Terebratula carnea J. Sowerby 1812 and Terebratula elongata J. de C. Sowerby
1823 are among the species of terebratulids most quoted in the literature on the
Upper Cretaceous White Chalk of northern Europe. Davidson (1854 : 67) placed
T. elongata in synonomy with T. carnea and figured several specimens from the
Upper Campanian of Norfolk.
The English Campanian-Maastrichtian terebratulids were treated comprehen-
sively by Sahni (1925, I925a, 1929, 1958). In 1925 he based his work on material
in the Institute of Geological Sciences, London, and the Castle Museum, Norwich.
Since he had seen the collections of neither Sowerby nor Davidson in the British
Museum (Natural History), London, he found it impossible to identify any of the
specimens available to him with the true T. carnea and T. elongata. Nevertheless,
he erected four new genera to cover what different authors until then had called T.
carnea and T. elongata, viz. Pulchrithyris, Carneithyris, Chatwinothyris and Ellipso-
thyris. In the same paper Sahni (1925) erected the following 13 species :
Pulchrithyris gracilis Magnithyris magna
P. extensa Chatwinothyris subcardinalis
Carneithyris subpentagonalis Ch. symphytica
C. circular is Piarothyris rotunda
C. variabilis Ellipsothyris similis
C. acuminata Ornithothyris carinata
C. norvicensis
Shortly after this he (i925a) added the following five new species to the list :
Carneithyris daviesi Chatwinothyris curiosa
C. subovalis Ch. gibbosa
C. uniplicata
and, concerning the evolution and ontogeny of the species of Carneithyris, he arrived
at the following conclusions (ig25a : 502) :
1. That the type of hinge-parts and cardinal process is of considerable importance in the
study of Chalk Terebratulids.
2. That the cardinal process shows a distinct line of evolution in the genus Carneithyris
expressed by :
(a) Change in shape from pyramidal to globular.
(b) Greater and greater development of its apophyses.
(c) Change in position with respect to the surrounding hinge-parts.
3. That these changes are repeated in phylogeny as well as in ontogeny.
322 SAHNI'S TYPES
Sahni (iQ25a : pi. 25) arranged the following table to illustrate the changes in
ontogeny and phylogeny :
ontogeny phylogeny
Stage IV Carneithyris subpentagonalis (fig. i)
C. subpentagonalis (fig. 7) C. variabilis (fig. 2)
Stage III C. subpentagonalis (fig. 8) C. daviesi (fig. 3)
Stage II C. subpentagonalis (figs 9, 10) C. subovalis (fig. 4)
C. subovalis (fig. 5)
Stage I C. subpentagonalis (fig. n) C. uniplicata (fig. 6)
From this it must naturally follow that C. uniplicata is found in strata con-
siderably older than those bearing C. subpentagonalis and C. variabilis.
In 1929 the species erected formally and correctly in I925a Sahni again described
as new and, in addition, the new species Carneithyris ornata and Magnithyris truncata
were erected. In the same year he redescribed and refigured Carneithyris carnea
and C. elongata for the first time.
In 1958 Sahni published a description of the Campanian and Maastrichtian
terebratulids belonging to the Carneithyris group from A. W. Rowe's collection
which, in about 1926, had come into the possession of the British Museum (Natural
History) . No new species were described, but more than 50 specimens of Chatwino-
thyris subcardinalis were examined and 17 specimens of Carneithyris gracilis and two
of C. carnea from the Campanian of the Norwich area were also dealt with. Thus,
by 1958, 19 species of carneithyridines from the Upper Campanian and three species
from the Lower Maastrichtian of the Norwich area were known.
From the Maastrichtian Craie Phosphate de Ciply, Belgium, Sahni (1929 : 41-2)
erected the new species Chatwinothyris ciplyensis and placed some Danian specimens
known under the name 'Terebratula lens' Nilsson in Chatwinothyris.
Between 1925 and 1958 Carneithyris and Chatwinothyris were reported from the
Campanian, Maastrichtian and Danian of Sweden (Hagg 1940, 1954), Denmark
(Rosenkrantz 1945), Poland (Kongiel 1935) and Bulgaria (Tzankov 1940 ; Zak-
harieva-Kovaceva 1947). In 1965 Steinich monographed the Upper Lower Maas-
trichtian brachiopods from the island of Riigen, Germany, and gave an extremely
comprehensive description of Chatwinothyris subcardinalis, including a first descrip-
tion of its ontogeny and variation.
Muir-Wood (1965 : 799) erected a new subfamily of terebratulids, the Carneithyri-
dinae, represented only by the two genera Carneithyris and Chatwinothyris. Con-
cerning Pulchrithyris , Ellipsothyris , Magnithyris, Ornithothyris and Piarothyris she
wrote : 'These genera are considered to be variants of Carneithyris and not distinct
genera.'
The Upper Cretaceous terebratulids of the Middle Vistula valley, Poland, were
described by Popiel-Barczyk (1968). Among these were the carneithyridines
Carneithyris subpentagonalis, C. carnea and C. circularis from the Campanian and
Maastrichtian ; C. elongata from the Upper Maastrichtian ; and, in addition,
Chatwinothyris subcardinalis, Ch. curiosa and Ch. lens from the Upper Maastrichtian.
In her identification of the species she considered that external features were more
OF CARNEITHYRIDINAE 323
dependable than internal ones, and (1968 : 23, 30) that the cardinalia in each species
varied considerably, depending on the age of the individual specimen.
Asgaard (1970) discussed Sahni's specimens of Chatwinothyris lens and showed
that they were not the true Upper Danian Terebratula lens of Nilsson (1827) but the
slightly older Terebratula incisa Buch (1835) ; she considered furthermore that
Chatwinothyris was a synonym of Carneithyris.
Surlyk (1972 : 24) also considered Chatwinothyris to be congeneric with Carneithyris
and described the special adaptation of the Maastrichtian white chalk C. subcardinalis
to a free-living mode of life as a 'self-righting tumbler'.
IV. THE PROVENANCE OF THE TYPE MATERIAL
During the period 1925-27, when Sahni wrote his first three papers, practically
every carneithyridine in the collections of the British Museum (Natural History),
the Geological Survey of Great Britain, now the Institute of Geological Sciences,
London, and the Norwich Castle Museum was opened and dissected, and designated
as a type, figured or identified. Later the British Museum (Natural History) came
into the possession of A. W. Rowe's stratigraphically well-documented collection of
brachiopods, part of which formed the basis of Sahni's latest paper (1958) on the
British terebratulids, but these specimens were not dissected.
The classical 'Upper Chalk of Norwich, Zone of Belemnitetta mucronata' was long
considered a single stratigraphical unit and collectors and museum curators often
considered it unimportant to state on the labels from which pits the specimens
originated. However, the careful stratigraphical collections made by Rowe and
Brydone showed that the Upper Chalk of Norwich could be split up into Campanian
and Lower Maastrichtian parts (Brydone 1908, 1909, 1938). Mainly on the basis of
Brydone's work Peake & Hancock (1961 : 297, fig. 3) divided the classical Norwich
Chalk into six subdivisions :
estimated thickness
Paramoudra Chalk 23 m
Beeston Chalk 23 m
Catton Sponge Bed (a complex of incipient
hardgrounds at the top of :)
Weybourne Chalk 23 m
Eaton Chalk 15 m
Basal mucronata Chalk 15 m
Thus the Upper Campanian (zone of Belemnitella mucronata s.l.) is about 100 m
thick. Above this follows a Lower Maastrichtian series estimated to be about
33-5 m thick, which is only known well from glacially transported masses. The
Campanian/Maastrichtian contact has not yet been observed with certainty in the
Norfolk area (see p. 360). The subdivisions of Peake & Hancock (1961) will be used
in this paper.
324
SAHNI'S TYPES
The specimens in Sahni's material which have labels with a locality name other
than 'Upper Chalk, Norwich' originate from the following localities :
'Trowse.' According to the Sowerbys (1812, 1823) the types of Terebratula
carnea and T. elongata came from this locality. Several pits in the Trowse area in
high Beeston Chalk may have contributed towards what was called Trowse' on
early igth-century museum labels. Later on this designation might also have in-
cluded Whitlingham (Crown Point Pit), which was opened in the late igth century,
exposing high Paramoudra Chalk.
'Thorpe.' Several types are labelled 'Thorpe'. This locality name also covers a
number of pits which were found in the area stretching eastwards from near the
centre of Norwich to Postwick. Lollard's Pit was in high Beeston Chalk ; it was
the source of Mosasaurus remains and therefore might include some part of the
hardground complex which is considered to separate the Beeston Chalk from the
Paramoudra Chalk (Peake & Hancock 1970). The pit called St James's Hollow
was in strata of approximately the same age. Two large pits known as Thorpe
Hamlets were intensively worked in the early igth century and much material
collected by Fitch, King, S. Woodward and others may have come from here. These
pits were also in high Beeston Chalk. Further east of these was the locality known
as Thorpe Limekiln or Thorpe Lunatic Asylum Pit. The chalk in it was quite
markedly yellow and a section about 2 m high could still be seen when I visited it in
1962. The pit is considered to have been in high Paramoudra Chalk. It was
available to the early collectors, and later yielded much material to Rowe. The
pit at Thorpe Tollgate also contained yellow chalk from high Paramoudra Chalk and
was worked in the early igth century. Further east was the Postwick Grove pit
which exposed chalk of the same age as Thorpe Tollgate. These two pits exposed
possibly the highest in situ Paramoudra Chalk in Norfolk.
Household, earlier called Magdalen Chapel. From this pit Rowe collected many
large carneithyridines and according to E. F. Owen, N. B. Peake and C. J. Wood
(personal communications 1972) this was the pit which yielded most of Bayfield's
collection of extremely large, often gerontic specimens. Now in the British Museum
(Natural History), this formed an important part of Sahni's material ; it contains
eight of his types, two possible types (one of which is figured), one figured specimen
and three identified to species. The pit is considered to have been in Beeston Chalk
and probably high in the lower half of it.
- 'Catton.' Some of Sahni's material originated from 'Catton by Norwich' (collected
by H. M. Muir-Wood) and '? Norwich' (collected by Sahni). According to E. F.
Owen (personal communication 1971) Sahni and Muir-Wood visited the Norwich
area on one occasion guided by the late T. H. Withers, and collected in Attoe's Pit,
Catton. At that time this pit exposed Weybourne Chalk at the bottom, with the
Catton Sponge Bed complex at its summit, overlain by a considerable section in low
Beeston Chalk.
Trimingham. These outcrops of glacially transported masses along the coast
between Sidestrand and Mundesley have yielded much material to the old collections.
The masses were mapped and described in detail by Brydone (1908). Brydone
OF CARNEITHYRIDINAE 325
(1938 : 7) concluded that the lower part of the Trimingham Chalk was of approxi-
mately the same age as the White Chalk of Riigen, Germany, and the upper part
equivalent to the Tuffeau of Maastricht, Holland. The following subdivision by
Brydone of the Trimingham Chalk has also been used by Peake & Hancock (1961,
1970) and Wood (1967) :
estimated belemnite zones
thickness (Wood 1967)
Grey Beds c. 6-7 m base of Belemnella occidentalis
cimbrica Zone
White Chalk with 'Ostrea
lunata' c. 6-1 m
White Chalk without } B. occidentalis occidentalis Zone
'0. lunata' c. 2-7 m
Sponge Beds c. 3-7 m
„ , 7 T, , I restricted B. lanceolata Zone
Porosphaera Beds c. 4-3 m
According to Peake & Hancock (1961 : 323) the White Chalk with and without
'Ostrea lunata' yielded most of the old material labelled 'Trimingham'. F. Surlyk
(personal communication 1973) considers the Grey Chalk to belong to his Zone 5
on the basis of the brachiopods (Surlyk 1970) while the lower part of the Sponge Beds
and the Porosphaera Beds predate brachiopod zones known from the Lower Maastrich-
tian of Denmark.
The old collection of Norwich Castle Museum. This collection was the basis for
parts of Sahni's first paper (1925) and it contains ten types and two figured specimens
of carneithyridines. It contains specimens from the Fitch, King and S. Woodward
collections, but owing to inadequate curation at the beginning of this century the
original labels were separated from the specimens. Apart from figured specimens
and those marked with ink, it is impossible even to ascertain from which of the
classical collections the brachiopods came and their exact localities are unknown
(B. McWilliams, personal communication 1972).
For much of this section I am greatly indebted to Mr C. J. Wood, who has
generously put at my disposal his extensive knowledge on the stratigraphical position
of pits in the Norwich area, many of which are now obliterated.
V. REVIEW OF SAHNI'S MATERIAL OF CARNEITHYRIDINES
In this and the following sections the glossary of morphological terms used in the
Treatise on Invertebrate Paleontology, H (1965) will be followed. Specimens treated
in this chapter are housed in the British Museum (Natural History) (numbers with
B), the Institute of Geological Sciences (GSM) and the Norwich Castle Museum old
collections (CMN or KCN). A name in parentheses after the number of the specimen
is that of the collector ; following this is the locality as originally given. In the
plates no attempt has been made to retouch the photographs : the figures have been
largely arranged according to the development of the cardinalia.
326 SAHNI'S TYPES
Carneithyris cornea (J. Sowerby, 1812)
PI. i, figs 1-3 ; PL 3, fig. 3 ; PI. 5, fig. 9 ; Text-fig. 26
Lectotype (sel. Sahni, 1929) : B 49836 (Sowerby) Trowse' (PI. i, fig. i)
Sowerby, 1812 : 47 ; pi. 15, fig. 5
Sahni, 1929 : 31-2 ; pi. 4, fig. 34
The lectotype is here refigured.
Paralectotype ('Syntype' of Sahni) : B 49837 (Sowerby) Trowse' (PI. i, fig. 2)
Sowerby, 1812 : 47 ; pi. 15, fig. 6
Sahni, 1929 : pi. 9, fig. 26
The brachial valve of the 'syntype', last figured by Sahni, has since been lost and
only the pedicle valve remains.
'Plesiotype'1 of Sahni : B 45600 (Bayfield) 'Norwich' (PI. 3, fig. 3)
Sahni, 1929 : pi. 9, fig. 25
This is practically identical in cardinalia and external features with the paratype
B 45603 of C. circularis (PI. 3, fig. 2), also from the Bayfield collection. It is also
very similar to the holotypes of C. subovalis, C. uniplicata and Ellipsothyris similis
(PI. 4, figs 3, 9, 10).
Others : B 51289 (Rowe) 'Whitlingham'
Sahni, 1958 : 17 ; pi. 6, figs 8a-c
Of the three specimens from Rowe's collection, only this one has been returned
to it.
B 51274 and B 51288 (Rowe), said to be from Norwich
Sahni, 1958 : pi. 6, figs ga-c, zoa-b
These have not been found in the collection : the specimen now numbered
B 51274 is clearly not that which Sahni figured under that number (see p. 330).
? B 49852 (Davidson) Trimingham' (PI. i, fig. 3)
Davidson, 1854 : pi. 8, fig. i
This specimen was not mentioned by Sahni. Although it is said to be from
Trimingham, its pink colour shows it to be Campanian.
26 KCN and 27 KCN 'Upper Chalk, Norwich' (PI. 5, fig. 9 ; Text-fig. 26)
Sahni, 1929 : pi. 4, figs 20-23 i pi- 9» ngs 17-18
Sahni called these C. cf . carnea, but they are not mentioned in the text. 27 KCN,
here figured, has cardinalia of a type which very much resembles that of the holotypes
of Pulchrithyris gracilis and C. norvicensis (PI. 5, figs 7, n). 26 KCN has never been
dissected.
Terebratula carnea was the first carneithyridine brachiopod described and strictly
should have been chosen as the type of the genus Carneithyris. (Instead, C.
subpentagonalis was chosen.) The lectotype and 'syntype' are also from known
localities, in contrast to the types of C. subpentagonalis. The three specimens of C.
carnea with known localities are possibly from high Beeston Chalk (the types) and
1 The use of the term 'Plesiotype' is to be discouraged. It has been used in a variety of senses (Frizzell
1933 : 662; Fernald 1939 : 699), all of them unnecessary. Sahni did not define his use of the term.
OF CARNEITHYRIDINAE 327
Paramoudra Chalk (B 51289) ; this agrees well with their rather small size and thin
shells.
Carneithyris elongata (J. de C. Sowerby, 1823)
PL 2, figs 1-3 ; PI. 4, fig. 5
Lectotype : B 49823 (Sowerby) 'Trowse' (PI. 2, figs la-c)
Sowerby, 1823 : 49 ; pi. 435, fig. i
Sahni, 1929 : 32 ; pi. 6, fig. 19
Paralectotype ('Syntype' of Sahni) : B 49824 (Sowerby) Trowse' (PI. 2, figs 2a-b)
Sowerby, 1823 : pi. 435, fig. 2
Sahni, 1929 : 32
Tlesiotype' of Sahni : B 45243 (Muir-Wood) 'Catton Pit, north of Norwich' (PI. 4,
ng- 5)
Sahni, 1929 : pi. 4, figs 24-26 ; pi. 10, fig. 9
Others : B 6101 (Davidson ex Fitch) 'Upper Chalk, Norwich' (PI. 2, figs 3a-c)
Davidson, 1854 : pi- 8, fig. 3
The lectotype and syntype are both from Trowse, possibly the same locality which
yielded the types of C. carnea. Both specimens are small and rather thin-shelled
(PI. 2, figs i, 2). The 'plesiotype' might be from high Weybourne Chalk, the
Catton Sponge Bed, or low Beeston Chalk. Sahni did not mention the specimen
figured by Davidson which I have added here. Incidentally, Norwich Castle Museum
also claims that its specimen no. 2072 is the one which Davidson figured ; it is nearly
identical to the London specimen but, according to Davidson's own label, there can
be no doubt that B 6101 is the one which is figured. The cardinalia of the 'plesio-
type' closely resemble those of the 'plesiotype' of C. carnea (PL 3, fig. 3) and of the
paratype B 45604 of C. circularis (PL 4, fig. 7).
Carneithyris subpentagonalis Sahni, 1925
PL 7, figs 2, 3
Holotype : 8 KCN 'Upper Chalk, Norwich' (PL 7, fig. 2)
Sahni, 1925 : 365 ; pi. 23, fig. 15 ; pi. 24, fig. 13 ; pi. 25, fig. 3
Sahni, ig25a : 498 ; pi. 25, fig. i
Sahni, 1929 : 31 ; pi. 5, figs 30, 31 ; pi. 9, figs 5, 6
Paratype : GSM 44491 'Norwich' (PL 7, fig. 3)
Sahni, 1925 : pi. 24, fig. 2 ; pi. 26, fig. 3
Sahni, ig25a : pi. 25, fig. 7
Sahni, 1929 : pi. 9, fig. 7
Others : Davidson, 1854 : pi- 8, fig. 2 (Sahni (1925, 1929) considered this figure to
represent the species, but the original specimen seems to be lost)
Sahni, ig25a : pi. 25, figs 3-5, 8 (not 9-11 as stated by Sahni)
328 SAHNI'S TYPES
When Sahni erected Carneithyris in 1925 he chose this species as type. In the
collections today it is only represented by the two type specimens ; the specimens
representing the ontogenetic Stages I-III of C. subpentagonalis (iQ25a : PI. 25,
figs 3-5, 8) have not been identified.
Carneithyris circularis Sahni, 1925
PI. 3, figs i, 2 ; PI. 4, figs 6, 7
Holotype : 15 KCN 'Norwich' (PI. 4, fig. 6)
Sahni, 1925 : 365 ; pi. 24, fig. 14
Sahni, 1929 : 33
Paratypes : B 49862 (Davidson) 'Norwich' (PI. 3, fig. i)
Davidson, 1854 : pi. 8, fig. 5
Sahni, 1929 : pi. 5, figs 11-13
B 45602 (Bayfield) 'Norwich'
Sahni, 1929 : pi. 5, figs 8-10
B 45603 (Bayfield) 'Norwich' (PI. 3, fig. 2)
Sahni, 1929 : pi. 9, fig. 23
B 45604 (Bayfield) 'Norwich' (PI. 4, fig. 7)
Sahni, 1929 : pi. 5, figs 6, 7 ; pi. 9, fig. 24
The cardinalia of the holotype have not been previously figured. They are very
similar in morphology to those of the paratype of C. variabilis (PI. 7, fig. 4) and some-
what like those of the paratype of C. subpentagonalis (PI. 7, fig. 3).
Sahni (1929) stressed that this species differed from all other Carneithyris in its
circular outline, but it shares this feature with the lectotype and the 'plesiotype' of
C. carnea (p. 326), and the holotype of Magnithyris magna (p. 333).
Carneithyris variabilis Sahni, 1925
PI. 5, fig- i ; PL 7, fig. 4
Holotype : 14 CMN 'Chalk near Norwich' (PI. 5, fig. i)
Sahni, 1925 : 366
Sahni, 1929 : 34
Paratype : 13 CMN 'Chalk near Norwich' (PI. 7, fig. 4)
Sahni, 1925 : pi. 25, fig. 4
Sahni, ig25a : pi. 25, fig. 2
Sahni, 1929 : pi. 4, fig. 27
The holotype shows the cardinalia which are not completely dissected out ; they
are somewhat similar to those of the holotypes of C. acuminata (PI. 5, fig. 3) and
C. daviesi (PI. 6, fig. 3), and of the two possible paratypes of C. norvicensis, B 52067
and 645610 (PI. 5, fig. 8 ; PI. 6, fig. 5). The cardinalia of the paratype closely
resemble those of the holotype of C. circularis (PI. 4, fig. 6) and of the paratype of
C. subpentagonalis (PI. 7, fig. 3). While the outer shape of the paratype is very
OF CARNEITHYRIDINAE 329
much like the holotype of C. subpentagonalis , Sahni (1925 : 366) stressed that C.
variabilis had its symphytium hidden under the strongly incurved beak. He
(ig25a) considered C. variabilis as having reached a level of development between
his Stages III and IV.
Carneithyris acuminata Sahni, 1925
PI. 5, ng. 3
Holotype : 19 CMN 'Upper Chalk, Norwich'
Sahni, 1925 : 366 ; pi. 26, fig. 5
Sahni, 1929 : 33 ; pi. 5, figs 17-19 ; pi. 9, fig. 15
This species is represented by a single specimen. According to Sahni (1929 : 33)
it is distinguished from C. elongata by having a Very much more advanced' cardinal
process. However, the only type-specimen of C. elongata in which the cardinal
process is clearly visible is the 'plesiotype' (PI. 4, fig. 5) and in this the process would
appear to be at least as 'advanced' (in Sahni's terms) as that of C. acuminata.
Furthermore, the cardinal process of Ornithothyris carinata (PI. 5, fig. 2) is also
comparable in morphology.
Carneithyris norvicensis Sahni, 1925
PI. 5, figs 8, ii ; PI. 6, fig. 5 ; Text-fig. 2C
Holotype : GSM 44494 'Norwich' (PI. 5, fig. n)
Sahni, 1925 : 367 ; pi. 24, fig. 5 ; pi. 26, fig. i
Sahni, 1929 : 34 ; pi. 4, fig. 29
It is not known from which pit the holotype was collected.
Paratypes : ? B 52067 'No information' (PI. 5, fig. 8)
? B 45610 (Bayfield) 'Norwich' (PI. 6, fig. 5 ; Text-fig. 2C)
? B 51636 and B 51637 (Sahni) '? Norwich'
Sahni, 1925 : pi. 26, fig. 14
Sahni (1925 : 367) considered this species distinct, with its vascular markings
'arising from in between the muscle-marks (instead of from their anterior apices),
and forking as it were from the pseudoseptum'. PI. 5, fig. n and Sahni (1925 ;
pi. 24, fig. 5) show that what he interpreted as 'mantle impressions' are in reality
slight depressions on either side of the ridges that form the anterior prolongation of
Sahni's 'pseudoseptum' ; they represent a characteristic gerontic feature, like the
pitted callus deposits round the bases of the inner socket ridges. It is now impossible
to state which of the four specimens identified as C. norvicensis is the paratype figured,
but not mentioned, in 1925. Both those here figured have large, swollen cardinal
processes : the cardinalia of this nominal species are shown here for the first time.
B 51636 and B 51637 are probably from Attoe's pit, Catton (see p. 324). The first
of these two was originally about 42 mm long and has a somewhat thickened posterior
end ; the other has very strong callus deposits in the posterior part of the valves,
so much so that the cardinalia seem to sit astride a cushion.
330 SAHNI'S TYPES
Carneithyris subovalis Sahni,
PI. 4, figs 3, 4 ; Text-fig. 2A
Holotype : B 15159 (Bayfield) 'Norwich' (PI. 4, fig. 3 ; Text-fig. 2A)
? Sahni, iQ25a : 500 ; pi. 25, fig. 10 (not 4 or 5 as stated by Sahni)
Sahni, 1929 : 34 ; pi. 4, fig. 33 ; pi. 9, fig. 16
Paratype : Norwich Castle Museum (no number) 'Upper Chalk, Norwich' (PI. 4,
fig- 4)
Sahni, 1929 : pi. 4, figs 31, 32 ; pi. 10, fig. 17
? Sahni, ig25a : pi. 25, fig. n (not 4 or 5 as stated by Sahni)
Others : B 45659 (C. Birley) 'Norwich' (identified and dissected by Sahni)
B 15157 (Bayfield) 'Norwich' (called 'young specimen' by Sahni)
B 45652 (Bayfield) 'Norwich' (called C. subovalis (?) by Sahni)
B 44182 (Rowe) 'Edward's Pit (now Campling's) Household' (identified by
Sahni)
B 51274 (Rowe) 'Household' (identified by Sahni, not identical with the specimen
figured in 1958 with the same number, see p. 326)
None of the three specimens which were opened and dissected by Sahni resemble
either of the two specimens said to represent the species in his pi. 25, figs 4, 5. On
the other hand, the holotype and the paratype look much more like his pi. 25,
figs 10, n, and it would seem that the figures have been mistakenly interchanged,
as in pi. 25, fig. 9.
This species is considered to represent Stages I -II in the evolutionary tree. The
two unopened specimens from Rowe's collection came from Household Pit ( = Hag-
dalen Chapel) and the three specimens from Bayfield' s collection might have come
from the same. Thus, at least five of the specimens seem to have come from the
upper low Beeston Chalk, which is known for its large brachiopods.
Carneithyris uniplicata Sahni,
PI. 4, fig. 9
Holotype : GSH 48518 Thorpe' (PI. 4, fig. 9)
Sahni, ig25a : 500 ; pi. 25, fig. 6
Sahni, 1929 : 35 ; pi. 4, fig. 30 ; pi. 10, fig. 18
Others : GSH 48514 and 48515 'Whitlingham' (brachial and pedicle valve of the
same specimen identified by Sahni as C. cf. uniplicata)
In his original description of this species Sahni (i925a : 500) stressed 'the primordial
character' of its cardinal process and made it the representative of his Stage I in his
evolutionary tree of cardinal processes (see p. 322). This, however, does not fit
very well with the provenance of the material, which is from late Beeston Chalk to
Paramoudra Chalk. The incipient plication which is discussed on p. 361 also
supports the late age.
OF CARNEITHYRIDINAE 331
Carneithyris daviesi Sahni,
PI. 6, figs 1-4 ; PI. 7, fig. i and Text-fig. 2D
Holotype : B 45599 (Bayfield) 'Norwich' (PI. 6, fig. 3)
Sahni, ig25a : 500 ; pi. 25, fig. 9 (not 3 as stated by Sahni)
Sahni, 1929 : 36 ; pi. 9, fig. 10
Paratype : B 459 (Bayfield) 'Norwich' (PI. 6, figs i, 2 ; PI. 7, fig. i ; Text-fig. 2D)
Sahni, 1929 : pi. 5, figs 4, 5 ; ? pi. 9, fig. 8 ; pi. 9, fig. 9
Others : B 45642 (C. F. Cockburn) 'Norwich' (identified and dissected by Sahni)
(PI. 6, fig. 4)
The two type specimens are the largest and most gerontic carneithyridines in the
Bayfield collection. The paratype shows particularly extreme gerontic features :
PI. 6, fig. i and PI. 7, fig. i show the swollen and protruding cardinal process and the
thickened hinge region of the brachial valve in this specimen. The pedicle valve,
moreover, shows the most gerontic features to be seen in any Carneithyris in the
British collections (PI. 6, figs i, 2) ; the enormously thickened tooth bases overlap
but have not fused and a tube is left open for the pedicle case and its muscles.
There is a 'pearl' in the adductor muscle impression. The length of the pedicle
valve is 43 mm. The 'drawing of the brachial valve of a large specimen with
brachidium' (Sahni 1929 : pi. 9, fig. 8) has a remarkable resemblance to the paratype,
when the brachial valve of this is tilted slightly.
The holotype (PI. 6, fig. 3) also exhibits a swollen cardinal process and has some
callus deposits in the posterior part of the valves. The length of the pedicle valve
was c. 35-5 mm. The third specimen, B 45642, was not completely dissected by
Sahni, but nevertheless shows a cardinal process very much like that of the holotype ;
it is fairly thin-shelled and is only about 33 mm long.
C. daviesi was considered to represent Stage III in the evolution of cardinal
processes (Sahni I925a).
Carneithyris ornata Sahni, 1929
PI. 4, figs n, 12
Holotype : GSM 48498 Thorpe'
Sahni, 1929 : 35 ; pi. 4, fig. 28 ; pi. 10, fig. 22
The nominal species is represented by a single specimen, in which, apart from the
preserved original colour pattern, Sahni (1929 : 35) found 'a small septum in the
pedicle valve' and unusually shaped vascular markings. There is a slight ridge
between the ventral adjuster scars and the vascular markings are clear ; these, in
connection with the pitted callus deposits in the posterior part of the valves (PI. 4,
fig. 12), are gerontic features of this particular specimen.
332 SAHNI'S TYPES
Pulchrithyris gracilis Sahni, 1925
PL 5, figs 4-7
Holotype : GSM 48487 'Magdalen Chapel, Norwich' (PI. 5, fig. 7)
Sahni, 1925 : 362 ; pi. 23, fig. 6 ; pi. 24, fig. iaa
Sahni, 1929 : 36 ; pi. 5, figs 26-28 ; pi. 9, fig. n
Paratype : GSM 48485 'Harford Bridges' (PI. 5, fig. 6)
Sahni, 1925 : pi. 24, fig. 12
Sahni, 1929 : pi. 9, fig. 13
Others : B 46300 (Muir-Wood) 'Catton Pit, Norwich' (PI. 5, fig. 5)
Sahni, 1929 : pi. 9, fig. 12
B 98123 (J. Brown) 'Charing, Kent' (PL 5, fig. 4)
Sahni, 1929 : pi. 9, fig. 14
B 51492 (Rowe) 'Thorpe, Limekiln Pit'
Sahni, 1958 : 16 ; pi. 6, figs 7a-c
B 51271-51273 (Rowe) 'Mousehold'
B 51275, 51276 (Rowe) 'Whitlingham'
B 51277 (Rowe) 'Mousehold'
B 51278 (Rowe) 'Whitlingham'
B 51279-51281 (Rowe) 'Mousehold'
B 51282 (Rowe) 'Whitlingham'
B 51283, 51284 (Rowe) 'Mousehold'
B 51285 (Rowe) 'Whitlingham'
B 51286, 51287 (Rowe) 'Mousehold'
Sahni 1958 : 16 (B 51271-3, B 51275-87 inclusive)
GSM 48484, 48486 (J. H. Blake) Trowse' (identified by Sahni)
When the species was first erected it was intended to cover what some authors
had called Terebratula elongata. The genus Pulchrithyris was distinguished by having
a loop which was 'exceptionally flat, bow-shaped with anteriorly directed apex (a
very distinctive feature)' (1925 : 362). The peculiar loop can also clearly be seen
on pi. 23, fig. 6. Later Sahni made Pulchrithyris a synonym of Carneithyris ;
'Owing to its delicate character I was unable to obtain the brachial apparatus of
these two species without damaging the loop, and this led me into an error as to the
orientation of this latter structure in relation to the crura' (Sahni 1929 : 31). The
holotype was now figured with the loop glued on with the correct side up while the
loop of the paratype remained upside down, as it does to this day (PL 5, fig. 6 ; see
Sahni 1929 : pi. 9, fig. 13).
The holotype is from Magdalen Chapel ( = Mousehold) ; the label of the paratype
gives the locality erroneously as Lollard's pit, Thorpe (high Beeston Chalk), owing
to an incorrect transcription of information from the old catalogue. The actual
locality should be Harford Bridges which, according to C. J. Wood (personal com-
munication 1973), comprised at least three pits in the upper third of the Weybourne
Chalk.
OF CARNEITHYRIDINAE 333
Sahni (1929) figured two other specimens, one of which according to its label
would be from Charing, Kent (PI. 5, fig. 4). This must be an error, since from its
characteristic features and pink colour there is no doubt that it came from an Upper
Campanian locality in Norfolk. Later (1958) 17 specimens from Rowe's collection
were dealt with. Of these, n are from Household (the type locality), five from
Whitlingham and one from Thorpe, Limekiln Pit (not Thorpe St Andrew's as stated
on the label). Two specimens in the collections of the Institute of Geological
Sciences, both from 'Trowse', have been identified by Sahni as belonging to this
species. Thus the material of C. gracilis covers a stratigraphical range from high
Weybourne Chalk to high Paramoudra Chalk. All specimens of the nominal
species are rather small in comparison with many of the others, and none of the
opened specimens shows extreme gerontic features.
Pulchrithyris extensa Sahni, 1925
PI. 4, %. 8
Holotype : 7 KCN 'Upper Chalk, Norwich'
Sahni, 1925 : 363 ; pi. 24, fig. 15 ; pi. 25, fig. 8 ; pi. 26, fig. 8
Sahni, 1929 : 36 ; pi. 6, figs 29-31
In its present condition the single specimen has no brachidium. Sahni neither
figured nor described its cardinalia and brachidium, so it is difficult to see any reason
for placing it in the genus Pulchrithyris. Sahni considered it distinct through its
'much elongate and pod-shaped character'. Its cardinal process is slightly asym-
metrical but somewhat resembles that of Carneithyris ornata (PI. 4, fig. 12).
Magnithyris magna Sahni, 1925
PI. 4, fig. i ; PI. 5, fig. 10
Holotype : GSM 48488 Thorpe' (PI. 4, fig. i)
Sahni, 1925 : 367 ; pi. 23, fig. i ; pi. 24, fig. i ; pi. 25, fig. i
Sahni, 1929 : 39 ; pi. 5, figs 1-3 ; pi. 10, fig. 7
Others : B 15149 (Bayfield) 'Norwich' (PI. 5, fig. 10)
Sahni, 1929 : pi. 10, fig. 8
B 44680, 45609, 45611 (Bayfield) 'Norwich' (identified and dissected by Sahni)
B 45586 (Bayfield) 'Norwich' (called 'young' by Sahni)
B 45639 (C. F. Cockburn) 'Norwich' (identified and dissected by Sahni)
The genus Magnithyris is said to be distinct from Carneithyris in 'its peculiar obtuse
beak, its distinctive cardinal process and brachidium. The foramen ... is also
much larger than in species of Carneithyris, and the socket-ridges very much thinner'
(Sahni, 1929:39). PI. 4, fig. i shows the cardinalia, which somewhat resemble
those of M. truncata (PL 4, fig. 2).
The other figured specimen B 15149 has less feeble cardinalia than the holotype but
the transverse band, which is broken off, is concealed in matrix and the left cms is
30
334
SAHNI'S TYPES
glued on in the wrong position. The diameter of the pedicle foramen is 1-2 mm, but
several of the types of Carneithyris spp. have foramina of this order of size, e.g. C.
circularis (paratype B 49862), C. daviesi (paratype) and Ellipsothyris similis (holo-
type). Sahni (1929 : 38) erroneously called this specimen a paratype of Ellipsothyris
similis (see p. 335).
B 44680, 45609, 45611 have been dissected ; none of them shows particularly thin
socket ridges and the diameters of the pedicle foramina do not exceed 1-5 mm.
B 45586 has not been opened ; its pedicle valve is 29 mm long and its foramen is
i-o mm in diameter. B 45639 has cardinalia closely resembling those of M. tmncata
(PI. 4, fig. 2). This type of Carneithyris is discussed further on p. 360.
Magnithyris truncata Sahni, 1929
PI. 4, ng. 2
Holotype : B 45606 (Bayfield) 'Norwich'
Sahni, 1929 : 39 ; pi. 5, figs 14-16 ; pi. 10, fig. 6
This species is represented by a single specimen ; its shell is thin and transparent,
the cardinalia are likewise very delicate and the foramen is large and labiate. For
further discussion of this extreme variant of Carneithyris see p. 360.
Piarothyris rotunda Sahni, 1925
PI. 3, fig- 4
Holotype : 18 KCN 'Upper Chalk Norwich'
Sahni, 1925 : 370 ; pi. 23, fig. 14 ; pi. 24, fig. n ; pi. 25, fig. 6 ; pi. 26, figs 6, 12
Sahni, 1929 : 37 ; pi. 5, figs 23-25 ; pi. 10, fig. 20
This single specimen, on which the genus Piarothyris was founded, was considered
a Carneithyris by Muir-Wood (1965 : 799). However, it possesses all the charac-
teristics of a Gibbithyris. The figure shows the feeble, transverse cardinal process,
the ventrally convex hinge-plates and the dorsally directed crura bases. To judge
from its external characters, the specimen may have come from a horizon rich in
brachiopods in the upper part of the Micraster coranguinum Zone (Santonian) in
south-east England (C. J. Wood, personal communication 1970). A tiny sample of
chalk matrix was taken from the cardinalia, but an analysis of the coccoliths in it
by Dr K. Perch-Nielsen of Copenhagen revealed only undiagnostic, long-ranged
forms.
Ellipsothyris similis Sahni, 1925
PI. 4, fig. 10 ; PI. 7, fig. 5 and Text-fig. 2E
Holotype : 14 KCN 'Upper Chalk Norwich' (PI. 4, fig. 10)
Sahni, 1925 : 371 ; pi. 23, fig. 13 ; pi. 24, fig. 8 ; pi. 25, fig. 9
Sahni, 1929 : 38 ; pi. 6, figs 12-15 ; pi. 9, fig. 22
OF CARNEITHYRIDINAE 335
? Paratype : B 45653 (Bayfield) 'Norwich' (PI. 7, fig. 5 ; Text-fig. 2E)
Sahni 1929 : pi. 9, fig. i (in the text, p. 38, B 15149 is said to be a paratype, but
this specimen is figured on pi. 10, fig. 8 as Magnithyris magna)
Others : B 45629 (J. F. Walker) 'Norwich' (identified and dissected by Sahni)
The genus Ellipsothyris is based on the cardinal process being 'ellipsoidal with
flat dorsal surface, bearing two very incipient knobs postero-laterally and a median
one' and the brachidium being 'narrow posteriorly, comparatively broad anteriorly'.
The type of cardinal process (PI. 4, fig. 10) is very similar to that of Carneithyris
circularis (645604, PI. 4, fig. 7). The brachidium of the holotype is only partly
dissected out of the chalk matrix and is now detached from the valve ; its apparent
shape in Sahni's illustration (1929 : pi. 9, fig. 22) is mainly due to retouching of the
photograph. The presumed paratype differs markedly from the holotype, having
completely fused Chatwinothyris-like cardinalia and a fairly parallel-sided brachidium
(PI. 7, fig. 5 and Text-fig. 2E). The third identified specimen has cardinalia of a
more swollen type than those of the holotype.
Ornithothyris carinata Sahni, 1925
PI. 5, fig. 2
Holotype : 17 KCN 'Upper Chalk Norwich'
Sahni, 1925 : 374 ; pi. 23, fig. 2 ; pi. 24, fig. 6 ; pi. 25, fig. 5
Sahni, 1929 : 44 ; pi. 6, figs 27, 28 ; pi. 10, fig. 19
The genus and species are represented by a single specimen. Sahni stressed the
importance of the 'conspicuous carination of its ventral valve, which points to a
sulcate ancestry' and of the transverse band of the brachidium which 'shows a
sudden arching up in the middle, producing a slight break in the curve and forming
as it were a sub-arch' (Sahni 1925 : 374 ; 1929 : 44). However, Sahni's illustration
(1929 : pi. 6, fig. 28) does not show any conspicuous carination of the pedicle valve,
and I was unable to see it on the remains of the specimen. The 'sub-arch' on the
loop is no more accentuated than in other terebratulids, so far as can be seen, since
the brachidium is partly covered by matrix (PI. 5, fig. 2). In shape and preservation
the cardinalia are practically identical with those of C. acuminata (PI. 5, fig. 3).
Chatwinothyris subcardinalis Sahni, 1925
PL 8, figs 1-4
Holotype : GSM 44501 (C. Reid) Trimingham Foreshore, 0. vesicularis Bed' (PI. 8,
fig- i)
Sahni, 1925 : 369 ; pi. 23, fig. 9 ; pi. 24, fig. 4a ; pi. 26, fig. 4
Sahni, ig25a : 499 ; pi. 25, fig. 12
Sahni, 1929 : 40 ; pi. 5, figs 20-22 ; pi. 10, fig. 4
Paratype : B 46326 (A. Laur) 'Isle of Riigen, Germany' (PI. 8, fig. 2)
Sahni, 1925 : pi. 24, fig. 4
Sahni, 1929 : pi. 6, figs 10-12 ; pi. 10, fig. i
336 SAHNI'S TYPES
Others : B 46327 and B 21266 (A. Laur) 'Isle of Riigen, Germany' (PI. 8, figs 3, 4)
Sahni, 1929 : pi. 10, figs 2, 3
B 51046, 51049 (Rowe) Trimingham, lunata reef
Sahni, 1958 : 15 ; pi. 5, figs la-c, 2a-c
B 51087, 51058 (Rowe) 'Trimingham, "non-lunata" reef
Sahni, 1958 : pi. 5, figs 3, 4
B 51060 (Rowe) 'Trimingham' (not present in the collection)
Sahni, 1958 : pi. 5, fig. 4x
The holotype is presumably from the lower part of the Grey Beds (C. J. Wood,
personal communication 1972) while the paratype and the two other specimens
figured in 1929 are from the Isle of Rugen, north Germany (Belemnella occiden-
talis Zone). Sahni (1958 : 15) mentioned that there were 'over fifty specimens'
in Rowe's collection ; the specimens figured in 1958 were all from the Trimingham
foreshore, from 'Ostrea lunata' Beds and Grey Beds (see p. 325).
The genus Chatwinothyris, of which Ch. subcardinalis is the type, is distinguished
from Carneithyris by having indistinct beak ridges and a pin-hole foramen. Further-
more, 'in Carneithyris there is no tendency towards fusion of cardinalia, which is an
important feature of Chatwinothyris' (Sahni, 1929 : 40).
As can be seen from the figures, this species was permitted unusual freedom of
variation in internal characters by its author. The cardinalia of the holotype and
B 21266 (PI. 8, figs i, 4) show hardly any fusion (compare Popiel-Barczyk 1968 : pi.
9, fig. i ; pi. 3, fig. 5). The paratype (PI. 8, fig. 2) has completely fused cardinalia
and looks much like the specimens figured by Steinich (1965 : text-fig. 27(3)) from
the Lower Maastrichtian of Riigen and by Popiel-Barczyk (1968 : pi. 8, fig. 7) from
the Upper Maastrichtian of Poland. The paratype of Ch. subcardinalis is not quite
as advanced in its fusion as the holotype of Ch. curiosa (PI. 8, fig. 5). B 46327
(PI. 8, fig. 3) has nearly completely fused cardinalia, though not to the degree of
those of the paratype, and the flaps on the sides of the diductor muscle scars have
united to form tubes which surrounded the posterior part of the diductor muscles.
A similar development is shown by the specimen figured by Steinich (1965 : text-fig.
27(4)). Popiel-Barczyk (1968 : pi. 5, fig. 6) illustrated under the name Carneithyris
carnea another specimen showing this development, and in pi. 9, fig. 3, a more gerontic
specimen of Ch. subcardinalis, both from the Upper Maastrichtian of Poland.
Chatwinothyris symphytica Sahni, 1925
PI. 2, fig. 4 and Text-fig. 2F
Holotype : GSM 47523 'Chalk near Norwich'
Sahni, 1925 : 369 ; pi. 23, fig. 7 ; pi. 24, fig. 7 ; pi. 26, fig. 9
Sahni, 1929 : 42 ; pi. 10, fig. 13 (called Ch. (?) symphytica in the text to the figure)
This single specimen shows no tendency to a fusion of the cardinalia, which should
be the main feature separating Chatwinothyris from Carneithyris. Sahni (1925,
1929) himself mentioned this, but for reasons unknown preferred to retain this
OF CARNEITHYRIDINAE 337
specimen in Chatwinothyris. The specimen is gerontic, with pitted callus deposits
in the posterior part of the valves, and the extreme development of the cardinal
process can be taken to be a result of old age as in the holotype and paratype of
Carneithyris daviesi (PI. 6, fig. 3 ; PI. 7, fig. i).
Chatwinothyris curiosa Sahni,
PI. 8, fig. 5
Holotype : B 45669 (Savin) Trimingham, Zone of Ostrea lunata'
Sahni, iQ25a : 499 ; pi. 25, fig. 13
Sahni, 1929 : 43 ; pi. 6, fig. 26 ; pi. 10, fig. 12
Sahni, 1958 : 15 ; text-fig. 3
The original description (ig25a : 499) reads as follows : 'Here the socket-ridges
and the crural bases are somewhat more developed and the process of fusion has gone
a step further, so much so that no trace whatever is left of the cardinal process. Its
position is now occupied by a narrow flat platform bounded laterally by the partially
overhanging and fused crural bases and socket-ridges. Hence it follows that the
diductor muscles, in this case, would be attached to this platform instead of directly
to the cardinal process, and that the partial articulatory function of the latter has
been assumed by the cardinalia.' The specimen figured in pi. 25, fig. 13 has no loop
and apparently a gaping hole where the cardinal process should have been. In
1929 (pi. 10, fig. 12) a transverse band has curiously appeared which shows a striking
colour difference from the cardinalia. The species was discussed again by Sahni
(1958 : 15) under the genus Chatwinothyris : 'The cardinal process in such forms
becomes atrophied and its function is relegated, partly at any rate, to the fused
cardinalia. In extreme cases the cardinal process becomes almost completely
resorbed, e.g. in Chatw. curiosa.'
An examination of the holotype showed that the gaping black hole on the 1925
illustration was in fact white chalk completely filling the space between the diductor
muscle attachment area and the umbo of the valve. When this chalk was removed
the diductor impressions could be seen (PI. 8, figs 5a, b). The curious transverse
band is glued onto the interior sides of the crura and thus does not fit this specimen,
but must have been derived from a smaller one (PI. 8, figs 5c, d). Furthermore, this
transverse band has the pinkish colour typical of Campanian Carneithyris while the
rest of the valve is of the greyish colour typical of beekitized Maastrichtian specimens.
Specimens with completely fused cardinalia like the holotype are not uncommon in
the Maastrichtian (e.g. Nielsen 1909 : pi. 2, figs 71, 75 ; Steinich 1965 : 43, figs 27(3),
32 ; Popiel-Barczyk 1968 : text-fig. 12, pi. 10, figs 1-5). Furthermore, both the
paratype of Chatwinothyris subcardinalis and the paratype of Ellipsothyris similis
belong to this type. The tendency towards a complete obliteration of the boundaries
between the different elements in the cardinalia is very strong in the Maastrichtian
specimens as a result of the general thickening of the posterior part of the shell.
Growth studies (Steinich 1965 : text-figs 27 and 29-31) and cellulose peels of serial
sections show that a gradual fusion of the cardinalia takes place and it is not a case
338 SAHNI'S TYPES
of suppression or even resorption of the cardinal process as postulated by Sahni.
(It is intended to publish serial sections of Carneithyris from the Danish Maastrichtian
and Danian in a later study now under preparation.) I therefore see no reason to
consider B 45669 as representing a separate species, but take it to be well within the
variation of Carneithyris subcardinalis.
Chatwinothyris gibbosa Sahni,
PI. i, fig. 4
Holotype : B 45670 (Savin) Trimingham, Zone of Ostrea lunata'
Sahni, iQ25a : 499 ; pi. 25, fig. 14
Sahni, 1929 : 43 ; pi. 5, figs 32, 33 ; pi. 10, fig. 21
In the original description (ig25a : 499) Sahni pointed out that in Ch. gibbosa
'the degree of development and fusion reached by the hinge-parts is about the same
as in C. subcardinalis, but the former species can be easily distinguished from the
latter by its marked gibbous shell and mesothyrid foramen'. As can be seen from
1929 : pi. 5, fig. 33, the valves are gaping and this has added c. 1-5 mm to the
thickness. In his generic diagnosis Sahni (1929 : 40) wrote 'beak-ridges feeble, so
that it is impossible satisfactorily to define the position of the foramen with regard
to these'. I consider that the position of a pin-hole foramen relative to beak ridges
which are at best very indistinct and in most cases missing entirely is a character of
no specific value.
The specimen is considered to fall well within the variation of Carneithyris
subcardinalis.
V. DISCUSSION
Studies of living and fossil communities of brachiopods have shown that several
species of the same genus can co-exist in the same environment. For example, in
the Caribbean Sea off Barbados, three species of Argyrolheca can be found attached
to the same sponge (unpublished observation). Similarly, three closely related
genera of micromorphic cancellothyridines represented by five species adapted to
the same mode of life occur in the Maastrichtian white chalk of Denmark (Surlyk
1972).
On the other hand, it is not easy to accept that six closely related genera represented
by 18 species could have existed in the Upper Campanian sea of the Norwich area,
of which at least nine species probably occur together at the same horizon in the
Beeston Chalk. This high degree of apparent speciation in an environment offering
a rather limited variety of ecological niches appears to be taxonoinic rather than
ecological and to be due to excessive 'splitting'.
The six genera of carneithyridines, represented by 18 species, were erected by
Sahni on the basis of about 55 specimens in museum collections. Because of this
limited material it is very difficult to identify any new material with the original
type series. Sahni allowed single species little freedom of variation and his diagnoses
were based on minor differences in outline of the shells, the size of the pedicle foramen,
OF CARNEITHYRIDINAE 339
the curvature of the beak and the development of beak ridges. Small differences in
the shape of the muscle impressions and cardinalia were also considered important.
Thus, with new material at hand, the student of carneithyridines has one of two
courses open to him. Either he must continue to attempt to split the group up on
the basis of Sahni's species characters, or he must combine some of the existing
genera and species in order to create broader species which can be identified easily
and so prove useful to the stratigrapher and field geologist. On the basis of a study
of new material in the English collections and observations in the field I have chosen
to follow the latter course.
Material
By 1929, Sahni's studies seem to have been based on about 55 specimens of
Campanian carneithyridines. Since that time the British Museum (Natural History)
has come into possession of A. W. Rowe's large collection of Carneithyris ; the
Institute of Geological Sciences, London, has profited from C. J. Wood's intensive
collecting in the extant exposures of Norfolk chalk ; and the Norwich Castle Museum
has obtained R. M. Brydone's collection of Campanian carneithyridines, to which the
collections of M. Leader and J. Goff have now been added.
The new material is stratigraphically well zoned. It has also the advantage that
it consists not only of perfect but also of crushed and incomplete specimens, thus
offering a good view over the internal and external features and their variation.
This contrasts with the general attitude of collectors in the igth century which led
to the selection of very large, perfect specimens. There was consequently an un-
intentional bias towards the gerontic end of the spectrum of variation.
Fig. i shows the material used in this chapter. An attempt has been made to
list the localities in stratigraphical order while the columns in mutual contact signify
localities considered to be of the same age or with stratigraphical overlap. The
figure also aims to give a visual impression of the quantitative distribution of the
material. Altogether 214 specimens have been measured for a statistical analysis
of the external characters.
Campanian carneithyridines so far have been found only in chalk ranging from
the upper third of the Weybourne Chalk to the top of the Paramoudra Chalk ;
according to Peake & Hancock (1961) this comprises about 55 m of chalk. The
material from Bramerton is included here with the Campanian specimens because it
has 'Campanian' cardinalia and colouration, in contrast to the Maastrichtian
Carneithyris subcardinalis. But according to C. J. Wood (personal communication
1972), Bramerton is of Maastrichtian age although the small exposure in the river-
bank has so far yielded only Belemnitella and no Belemnella.
The phylogenetic tree of Sahni (i925a)
According to Sahni (i925a : 498) this 'tree', in combination with Stages I to IV
of the ontogeny of the cardinalia in C. subpentagonalis , 'confirms the dictum that
Ontogeny repeats Phylogeny' (see p. 322). However, the provenance of the
individual species of the tree suggests that the stratigraphical order in which they
have been placed may be questioned.
34°
SAHNI'S TYPES
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OF CARNEITHYRIDINAE
341
Carneithyris uniplicata was placed at the root of the tree. As mentioned on p. 330,
however, the holotype is from high Beeston Chalk or high Paramoudra Chalk and
the other specimen is from high Paramoudra Chalk. At least five of the seven known
specimens of C. subovalis probably came from low Beeston Chalk. One of the three
known specimens of C. daviesi is extremely gerontic and the two types are supposed
to be from low Beeston Chalk. C. variabilis is represented by two specimens from
the old collections of Norwich Castle Museum and are therefore unlocalized. The
crown of the tree is C. subpentagonalis but it is not known from which horizons the
two types came. The three unlocated specimens of this species figured by Sahni
(iQ25a : pi. 25, figs 3-5 and 8) may be in his private collection and may therefore
have come from Attoe's Pit, Catton (p. 324) ; they may thus be from highest
Weybourne Chalk, the Catton Sponge Bed or low Beeston Chalk. It is thus clear
that the species chosen by Sahni cannot represent a phylogenetic lineage.
Morphology of the cardinalia
Fig. 2 illustrates the six different types of cardinalia met with in the Upper
Campanian carneithyridines. In Table i, Sahni's figured specimens and those
which he dissected and identified to species have been grouped according to type of
FIG. 2. Six different types of cardinalia in Carneithyris. A : C. subovalis, holotype ; B
C. cf. carnea, 27 KCN ; C : C. norvicensis, B 45610 ; D : C. daviesi, paratype ; E
Ellipsothyris similis, ? paratype ; F : Chatwinothyris symphytica, holotype.
342 SAHNI'S TYPES
TABLE i
Sahni's specimens grouped according to the type of cardinalia
TYPE A : Slender, conical to hemispherical cardinal process with or without ridges or flaps
• between or around the diductor impressions ; socket ridges and crural bases not thickened.
Carneithyris subovalis, holotype B 15159 (Fig. 2 A ; PI. 4, fig. 3) ; unnumbered paratype (PI. 4
fig. 4)
C. carnea, 'plesiotype' B 45600 (PI. 3, fig. 3)
C. elongata, paralectotype B 49824 (PI. 2, fig. 2) ; 'plesiotype' B 45243 (PI. 4, fig. 5)
C. uniplicata, holotype GSM 48518 (PL 4, fig. 9)
C. circularis, holotype 15 KCN (PI. 4, fig. 6) ; paratypes B 45603, B 45604 (PL 3, fig. 2 ; PL 4,
fig- 7)
C. ornata, holotype GSM 48498 (PL 4, fig. 12)
Pulchrithyris extensa, holotype 7 KCN (PL 4, fig. 8)
Ellipsothyris similis, holotype 14 KCN (PL 4, fig. 10)
Magnithyris magna, holotype GSM 48488 (PL 4, fig. i)
M. truncata, holotype B 45606 (PL 4, fig. 2)
TYPE B : Cardinal process more swollen and protruding than in type A ; socket ridges and
crural bases somewhat thickened.
Carneithyris cf. carnea, 27 KCN (Fig. 2B ; PL 5, fig. 9)
C. variabilis, holotype 14 CMN (PL 5, fig. i)
C. acuminata, holotype 19 CMN (PL 5, fig. 3)
C. norvicensis, holotype GSM 44494 (PL 5, fig. n)
Pulchrithyris gracilis, holotype GSM 48487 (PL 5, fig. 7) ; paratype GSM 48485 (PL 5, fig. 6) ;
B 46300 (PL 5, fig. 5)
Magnithyris magna, ? paratype B 15149 (PL 5, fig. 10)
Ornithothyris carinata, holotype 17 KCN (PL 5, fig. 2)
TYPE C : Cardinalia intermediate between types B and D ; the specimens large and thick-
shelled.
C. norvicensis, ? paratype B 45610 (Fig. 2C ; PL 6, fig. 5) ; ? paratype B 52067 (PL 5, fig. 8) ;
B 51636 (not figured)
C. daviesi, holotype B 45599 (PL 6, fig. 3) ; B 45642 (PL 6, fig. 4)
C. subpentagonalis , paratype GSM 44491 (PL 7, fig. 3)
C. variabilis, paratype 13 CMN (PL 7, fig. 4)
Pulchrithyris gracilis, B 98123 (PL 5, fig. 4)
TYPE D : Cardinalia strongly thickened with extremely swollen and protruding cardinal process
with ridges and flaps.
C. daviesi, paratype B 459 (Fig. 2D ; PL 7, fig. i)
C. subpentagonalis, holotype 8 KCN (PL 7, fig. 2)
TYPE E : Swollen, completely fused cardinalia.
Ellipsothyris similis, ? paratype B 45653 (Fig. 2E ; PL 7, fig. 5)
TYPE F : Cardinalia strongly thickened and completely dominated by the swollen cardinal
process.
Chatwinothyris symphytica, holotype GSM 47523 (Fig. 2F ; PL 2, fig. 4)
Carneithyris norvicensis, B 51637 (not figured)
OF CARNEITHYRIDINAE 343
cardinalia. Comparison of Sahni's material with the new, dissected material in the
English collections clearly shows a general tendency in the development of the
cardinalia. Types A and B are found in specimens showing no gerontic features.
Type C appears in specimens which show incipiently gerontic features such as
crowding of growth lines at the frontal margin and callus deposits around the teeth
bases and the dental sockets. Type D is common in gerontic specimens while E and
F are rarely met with and found only in specimens with extremely gerontic features
(e.g. the paratypes of Carneithyris daviesi and Ellipsothyris similis).
It can furthermore be seen in Table i that in some of Sahni's species the specimens
in the type series belong to different groups. In most cases, however, Sahni's diag-
noses took account of the cardinalia of the holotypes only, as e.g. in E. similis.
The large numbers at hand demonstrate that the cardinalia of the carneithyridines
are subject to great variation, which is dependent on the ontogenetic age of the
single individual and not on its geological age. From the upper part of the Wey-
bourne Chalk to the top of the Campanian (including Bramerton) there seems to be
no trend in the development of the cardinalia towards any particular type. I agree
here with Popiel-Barczyk (1968 : 23, 24) that the use of minute differences in the
cardinalia for distinguishing between species is highly questionable when other
features are not taken into account.
External morphology
Sahni (1925, 1929) stressed the importance of the external morphology in dis-
tinguishing between the different genera and species of carneithyridines. However,
it is notoriously difficult to describe in words a terebratulid in which the two valves
are equally biconvex and which has a rectimarginate frontal commissure, strongly
incurved beak, indistinct to missing beak ridges, pinhole foramen and no ornament.
It is even more difficult to word a differential diagnosis for such forms. As is seen
in Sahni (1929 : 57), such short descriptions of the different species must have almost
identical wording. It is clear that a statistical approach must be adopted.
In most cases Sahni (1925, 1929) only stated the dimensions of the holotypes and
of these only the length of the brachial valve was given in mm while the width,
thickness and total length were given as percentages. Most of these types have
since been dissected and broken. For statistical purposes I have therefore had to
recalculate their dimensions in mm from Sahni's percentages. But in some cases,
where the specimen has survived undamaged, I have been able to check the measure-
ments (e.g. the lectotypes of C. carnea and C. elongata, and the holotype of C. ornata).
Some of the recalculated dimensions differ from corresponding direct measurements
by as much as 5 mm.
The following statistical analyses are based on the length of brachial and pedicle
valves, width and thickness. In addition, the diameter of the pedicle foramen and
the curvature of the beak have been measured. These measurements are not used
in the analyses since it is quite clear that there is no correlation between the curvature
of the beak and the outline of the shell, though this was often stressed by Sahni in
the diagnosis of a species. The diameter of the foramen is very variable, from
X
SD
CV
OR
N
2O-2
2-50
12-38
16-5-23-4
8
18-4
2-12
11-52
15-2-21-0
8
I7-3
2-18
12-6
14-4-20-4
8
10-8
2-45
22'7
7-5-I3-9
7
X
SD
CV
OR
N
17-6
2-04
n-6
I5-3-I9-I
3
16-0
i-55
25-8
I4-3-I7-3
3
J5-4
1-27
8-3
14-4-16-8
3
8-9
1-76
19-8
6-9-10-0
3
X
SD
CV
OR
25-6
4-60
18-0
17-6-33-0
23-4
4-32
18-5
16-0-30-5
22-2
3.92
17-7
15-8-30-1
13-4
3-18
23-7
8-5-18-6
344 SAHNI'S TYPES
TABLE 2
Monovariate analyses of specimens of Carneithyridinae from different localities
Bramerton
Lp in mm
Lb in mm
W in mm
T in mm
Wroxham Pipeline
Lp in mm
Lb in mm
W in mm
T in mm
Thorpe Limekiln
Lp in mm
Lb in mm
W in mm
T in mm
Whitlingham (Crown Point)
Lp in mm
Lb in mm
W in mm
T in mm
'Trowse'
Lp in mm
Lb in mm
W in mm
T in mm
'Thorpe'
Lp in mm
Lb in mm
W in mm
T in mm
Frettenham
Lp in mm
Lb in mm
W in mm
T in mm
X
SD
CV
OR
N
25-6
4-68
18-3
18-0-34-2
16
23H
4-30
18-4
16-3-31-5
16
22-3
3-99
17-9
15-6-31-3
16
14-1
3-25
23-1
8-4-19-4
16
X
SD
CV
OR
N
23-6
6-68
28-3
16-2-29-2
3
21-3
6-09
28-6
14-6-26-5
3
2I-O
6-90
32-9
14-6-28-3
3
13-2
4-69
35-5
8-0-17-1
3
X
SD
CV
OR
N
3i-5
5-86
18-6
22-6-38-0
6
28-4
4-82
17-0
20-6-34-0
6
27-6
5H5
19-7
21-0-36-0
6
17-6
4-42
25-1
11-8-23-8
6
X
SD
CV
OR
N
31-1
6-57
2I-I
23-8-37-8
7
28-3
4-72
16-7
21-7-34-3
7
26-9
3-37
12-5
22-0-31-6
7
17-4
3-72
21-4
13-4-21-8
7
OF CARNEITHYRIDINAE 345
TABLE 2 (Continued)
Westlegate
X SD CV OR N
Lp in mm 27-5 5-05 18-4 21-0-35-0 7
Lb in mm 25-2 4-62 18-3 19-2-32-0 7
W in mm 24-6 4-79 19-5 18-8-30-4 7
T in mm 15-3 3-28 21-4 11-4-20-5 7
Caistor St Edmunds
X SD CV OR N
Lp in mm 22-5 4-45 19-8 14-5-31-0 13
Lb in mm 20-6 4-22 20-5 13-0-28-5 13
W in mm 20-8 3-83 18-4 14-0-29-0 13
T in mm 11-7 2-96 25-3 6-3-17-0 13
Mousehold
X SD CV OR N
Lp in mm 31-7 3-95 12-5 21-6-39-5 74
Lb in mm 28-7 3-55 12-4 20-0-36-0 74
W in mm 27-1 3-23 11-9 18-5-32-4 74
T in mm 18-1 3-01 16-6 10-6-26-0 74
Catton Grove + 'Catton'
X SD CV OR N
Lp in mm 28-3 5-87 20-7 13-8-43-9 31
Lb in mm 25-8 5-40 20-9 13-0-40-2 31
W in mm 23-9 4-65 19-5 12-5-36-0 31
T in mm 16-0 4-16 26-0 6-3-26-0 31
Harford Bridges
X SD CV OR N
Lp in mm 28-5 5-37 18-8 18-8-38-4 23
Lb in mm 26-0 4-94 19-0 16-8-35-5 23
W in mm 23-8 4-89 20-6 I^>'4~33'5 23
T in mm 16-8 3-76 22-4 10-0-22-0 23
Abbreviations. Lp : length of pedicle valve. Lb : length of brachial valve. W : width. T : thickness.
N: number of specimens. X: computed mean value. SD: standard deviation. CV: coefficient of vari-
ation. OR : observed range.
o-i mm to 2-0 mm, and cannot be connected with any particular shape of shell.
However, there may be a connection with the thickness of the valves since mature
specimens with large foramina tend to have thin valves.
Statistical analyses
The /-test was applied to the mean values of the lengths of the brachial valves for
pairs of the localities represented in Table 2 after the .F-test had shown that the
variances can be considered equal (Simpson et al. 1960). The results are given in
Table 3. They support the evidence of a decrease in size of mature specimens
towards the top of the Campanian given by the histograms in Fig. 3. The only
locality which shows an aberrant size distribution is Caistor St Edmunds which is of
approximately the same stratigraphical age as Westlegate and Mousehold.
346
SAHNI'S TYPES
TABLE 3
Monovariate analyses : the tf-test applied to the mean values of the
lengths of
the
brachial valves, for pairs of the localities represented in Table 2
t
df
< P
<
Bramerton versus Thorpe
Limekiln 3 -071 8
21
0-1%
i%
Bramerton versus Mousehold 8-1580
80
0-1%
Bramerton versus Harford
Bridges *4«i889
29
0-1%
Thorpe Limekiln versus Whitlingham 0-003
29
90%
Thorpe Limekiln versus 'Trowse' 0-7186
16
40%
50%
Thorpe Limekiln versus 'Thorpe' 2-3091
19
2%
5%
Whitlingham versus Mousehold 5-2807
88
0-1%
'Trowse' versus 'Thorpe'
1-9113
7
5%
10%
'Trowse' versus Mousehold 3-49i6
75
0-1%
'Thorpe' versus Mousehold 0-2186
78
80%
90%
Frettenham versus Whitlingham 2-6160
24
!%
2%
Frettenham versus Westlegate 1-2590
12
20%
30%
Frettenham versus Caistor St Edmunds 4-5096
18
0-1%
Frettenham versus Mousehold 0-2491
79
80%
90%
Westlegate versus Caistor
St Edmunds 2-2470
18
2%
5%
Caistor St Edmunds versus Whitlingham 1-7421
26
5%
10%
Caistor St Edmunds versus Mousehold 7'45°8
85
0-1%
Mousehold versus Catton Grove + 'Catton' *3'29O5
103
0-1%
i%
Mousehold versus Harford
Bridges *2-86i5
95
0-1%
i%
Catton Grove + 'Catton' versus Harford Bridges 0-1797
52
80%
90%
* In these cases the F-test gave a P< 5% ; nevertheless the *-test was made.
df : degrees of freedom.
10-
Whitlingham (Crown Point)
10-
B ram ton
"
3.
I
3.
, n FN
i 1 1 1 1
| , , ,
1 , , , ,
i
10.
"Trows*"
Thorp* Limekiln (=Lun
otic Asylum Pit)
3-
N = 3
3-
N= 15
i 1 l 1
| 1
' ' 5 K —
I"1—
-,
10-
N = 7
Thorp*
3-
5.
N = 6
1 -i- i i 1
1
' 1 1 1 10!
W*stl*gat*
2 24 26 28 30
32 34 36
I 14 16 18 20 11 24 26 28 30 32 34
3.
N = 7
23.
Mou».hold
20.
N=U74 °C
r *
Caistor St. Edmunds
N = 13
3.
15.
1
1
rn
-, 1 1 1
10.
Cotton Gray*
!2 24 26 28 30
i.
1
N = 10
• 1 ' 1
15'
10.
1 14 16 18 20 22 24 26 28 30 32 34 36
1 | '
Horford Bridgts
1
10.
"Catton"
N = 23
N=21
J.
^^"
P=l , f=
^^^
=; — ! 1
26 21 30 32 34 36 12 14 16 18 20 22
26 28 30 32 34 36 38 40
FIG. 3. Size-frequency histograms of the measurable specimens from 12 localities.
Abscissa : length of brachial valve in mm ; ordinate : number of specimens.
OF CARNEITHYRIDINAE
347
Figs 4-12 are length of brachial valve/width and thickness/width scatter diagrams
from the 12 localities used in the monovariate analyses. Regression lines (least
square method) are drawn for each graph and the equations for the lines are given
in Table 4. For the calculation of the regression lines the original measurements
have been used, since the scatter diagrams show a linear trend with an elliptical
distribution of the plots, and not a fan-shape which would have necessitated use of
logarithms (Christensen 1973, 1974).
TABLE 4
Equations for the regression lines of each graph shown in Figs 4-12
Bramerton
Thorpe Limekiln
Whitlingham (Crown Point)
Frettenham
Westlegate
'Trowse' + 'Thorpe'
Caistor St Edmunds
Household
Catton Grove + 'Catton'
Harford Bridges
Y = a + bX
Lb = 2-1036 + 0-9405 W
T = —7-1429 +
Lb = 0-2834 +
T = —5-6774 + O-6Q26W
Lb = 1-0461 + i -002 7 W
T = -0-4535 + 0-6527W
Lb = -8-2010 + I-3587W
T = -9-9033 + I-OI50W
Lb = 2-5293 + O-9226W
T = 1-5918 + 0-5588W
Lb = 3-4019 + o-8893\V
T = —2-0128 + o-
Lb = -1-6418 + i-07i3\V
T = —3-6525 + o-739iW
Lb = 1-7163 + 0-99&5W
T = —1-9247 + o-7399\V
Lb = —1-2261 + I-I2Q6W
T = -3-2015 + o-SoigW
Lb = 2-9904 + o-9663\V
T = —0-1951 + o-7i24\V
sd
r
N
0-8441
0-8095
0-9295
0-9533
8
7
1-4610
1-7081
0-9453
0-7712
15
15
1-6241
2-0052
0-9309
0-8022
16
16
1-2821
1-5976
0-9688
0-9198
7
7
1-4662
2-0793
0-9572
0-8156
7
7
1-9497
1-2374
0-9530
0-9699
9
9
1-0104
0-9I55
0-9733
0-9565
13
13
1-3918
1-8529
0-9187
0-7918
74
74
1-2518
1-8629
0-9737
0-8977
l\
1-5428
1-3599
0-9530
0-9348
23
23
sd: standard deviation of the regression line, r: coefficient of correlation. Other abbreviations as in
Table 2.
Though the regression lines were calculated on the bases of plots of mature and
gerontic specimens they can to some extent be compared with the growth curves
for the brachiopods. In order to test this, regression lines were calculated for most
of the localities on the basis of growth line measurements on the specimens. The
resulting regression lines were parallel to the straight middle part of the S-shaped
growth curve for the specimens (not figured here). The regression lines based on
growth line measurements were roughly parallel to the regression lines based on
plots of mature and gerontic specimens, though the first mentioned sloped slightly
348
SAHNI'S TYPES
O-i CD
S 3
03
IS.
II
&s
.2 pq
C o
•si
oJ -•
i§ 's
£ £
?^
^ IH
o o
OF CARNEITHYRIDINAE
349
.2
<« 3
7f\ VJ
£ s
J2 fo
o <u
5 a>
^^
a
cj
12
bo
a
35°
SAHNI'S TYPES
OF CARNEITHYRIDINAE
351
352
SAHNI'S TYPES
I
fa
S
9)
a
a
1
u it
O 00 O ^
OF CARNEITHYRIDINAE
353
more steeply and had a lower intercept on the ordinate. The two sets of regression
lines were tested by the /-test and in all cases the differences in slopes were found
to be insignificant (P > 80%), and thus the regression lines in Figs 4-12 can roughly
be considered to represent the straight middle part of the growth curves for the
specimens from the different localities.
The /-test was applied to the slopes of the regression lines for pairs of localities
after the .F-test had shown that the variances can be considered equal. The results
are given in Table 5. The differences in slope can nowhere be considered highly
significant.
TABLE 5
Bivariate analyses. Test for differences in the slopes of regression lines for the
pairs of localities shown in Table 3.
/
df
<P <
Bramerton versus Thorpe Limekiln
Lb/W
T/W
0-4000
1-2017
19
18
70%
20%
80%
30%
Bramerton versus Whitlingham (Crown Point)
Lb/W
*T/W
0-2260
1-1489
20
19
80%
20%
90%
30%
Bramerton versus 'Trowse' + 'Thorpe'
*Lb/W
T/W
0-1692
1-6169
13
12
80%
10%
90%
20%
Bramerton versus Frettenham
Lb/W
T/W
1-5974
0-1196
II
10
10%
90%
20%
Bramerton versus Westlegate
Lb/W
*T/W
0-0767
1-5342
II
10
90%
10%
20%
Bramerton versus Caistor St Edmunds
Lb/W
T/W
0-7001
1-7647
17
16
40%
5%
50%
10%
Bramerton versus Household
Lb/W
*T/W
0-0224
0-9147
78
77
90%
30%
40%
Bramerton versus Catton Grove + 'Catton'
Lb/W
*T/W
1-6147
0-75I5
35
34
10%
40%
20%
50%
Bramerton versus Harford Bridges
Lb/W
T/W
0-0980
1-4005
27
26
90%
80%
90%
Thorpe Limekiln versus Whitlingham
(Crown Point)
Lb/W
T/W
0-2612
0-2272
27
27
70%
80%
80%
90%
Thorpe Limekiln versus Household
Lb/W
T/W
0-4081
0-3345
85
85
60%
70%
70%
80%
Whitlingham (Crown Point) versus
Household
Lb/W
T/W
0-0583
0-6254
86
86
90%
50%
60%
'Trowse' + 'Thorpe' versus Household
Lb/W
T/W
1-1247
0-2172
79
79
20%
80%
30%
90%
'Trowse' + 'Thorpe' versus Harford Bridges
Lb/W
T/W
0-6657
0-0183
28
28
50%
90%
60%
354
SAHNI'S TYPES
TABLE 5 (Continued)
Frettenham versus Westlegate
Frettenham versus Caistor St Edmunds
Frettenham versus Household
Frettenham versus Harford Bridges
Westlegate versus Caistor St Edmunds
Westlegate versus Household
*
df
<P
<
Lb/W
T/W
2-1371
I -6606
10
10
5%
20%
10%
30%
Lb/W
T/W
1-8265
1-6494
16
16
10%
10%
20%
20%
Lb/W
T/W
2-0673
1-1835
77
77
2%
20%
5%
30%
Lb/W
T/W
2-0645
1-6614
26
26
2%
10%
5%
20%
Lb/W
*T/W
1-1150
1-1414
16
16
20%
20%
30%
30%
Lb/W
T/W
0-5711
1-0462
77
77
50%
20%
60%
30%
20 22 24 26 28 30 32 34 36 38 40mmW
FIG. 9. Length of brachial valve/width scatter diagram for Mousehold locality.
OF CARNEITHYRIDINAE
TABLE 5 (Continued)
df
<P
Lb/W
*T/W
0-6636
0-0054
83
83
50%
90%
60%
Lb/W
T/W
1-8403
0-6250
IOI
101
5%
50%
10%
60%
Lb/W
T/W
o-3738
0-2770
93
93
?o%
70%
80%
80%
Lb/W
T/W
2-0193
0-9154
50
50
5%
30%
10%
40%
Caistor St Edmunds versus Mousehold
Mousehold versus Catton Grove + 'Catton'
Mousehold versus Harford Bridges
Catton Grove + 'Catton' versus
Harford Bridges
* In these cases the F-test gave a P<5%', nevertheless the /-test was made.
Abbreviations as in Tables 2 and 3.
In Figs 13 and 14 the regression lines for the different localities have been super-
imposed to give a visual impression of similarities of growth in the specimens ; the
only aberrant localities are Frettenham and Bramerton. The material from
Frettenham shows a slightly more rapid growth in length of brachial valve than that
of the other localities, while both Bramerton and Frettenham show a steeper increase
in thickness with width than the other localities.
Twenty-seven specimens were plotted for length of brachial valve against width ;
these including the holotypes of Carneithyris subpentagonalis, C. circularis, C.
T -
mm
30.
28
26.
24.
22.
20.
18.
16.
14.
12.
10.
8.
6.
4.
2.
Mousehold N = 74
;% 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40mmW
FIG. 10. Thickness/width scatter diagram for Mousehold locality.
356
SAHNI'S TYPES
\
OF CARNEITHYRIDINAE
357
Ew . n .. B ••
r> r> o CM
O CD O
358
SAHNI'S TYPES
variabilis, C. acuminata, C. norvicensis, C. subovalis, C. daviesi, Pulchrithyris extensa,
Ellipsothyris similis, Chatwinothyris symphytica, Ornithothyris carinata, Magnithyris
truncata and paratypes of Carneithyris subpentagonalis, C. circularis, C. variabilis,
C. daviesi, Ellipsothyris similis and Magnithyris magna. They are all from old
collections with no locality specification and all were identified by Sahni. The
regression line was computed (least square method) and gave the following result :
Lb = 22-6890 + 0-331 iW ; sd = 3-8349 ; r = 0-4348. This regression line is
Lb
42.
40.
38.
36 .
34.
32.
30 _
28.
26.
24.
22.
20 _
18.
16.
14.
12,
10.
8
10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 mmW
FIG. 13. Length of brachial valve/width. Superimposed regression lines for the material
from the 10 localities used in the bivariate analyses, i : Bramerton ; 2 : Thorpe
Limekiln ; 3 : Whitlingham (Crown Point) ; 4 : Trowse' + 'Thorpe' ; 5 : Frettenham
(note the steep slope) ; 6 : Westlegate ; 7 : Caistor St Edmunds ; 8 : Household ; 9 :
Catton Grove + 'Catton' ; 10 : Harford Bridges, n : regression line based on the
27 gerontic specimens discussed on p. 359.
OF CARNEITHYRIDINAE
359
FIG. 14. Thickness/width. Superimposed regression lines for the same localities as in
Fig. 13. Note the steep slopes for Bramerton and Frettenham ; the two lines are
approximately parallel.
included in Fig. 13 (no. n) but shows a striking difference from the others. The
slope of the line reflects the upper part of the S-shaped growth curve of the brachio-
pods in general, demonstrating the slow growth of senile specimens. It was partly
on the basis of the differences in outline that Sahni established his many genera and
species ; the great variation in outline of these 27 senile specimens is well documented
by the low correlation coefficient.
In contrast to the 27 senile specimens, however, the types from known localities
fit well into the linear scatter plots, and the plots show high correlation, e.g. Trowse'
and Thorpe' (Fig. 7).
Conclusions
It can be concluded from the statistical analyses here offered that the present
material from known localities shows no significant differences in growth and outline
that can be used for differentiating species. The 27 unlocated senile specimens on
which 12 species were erected by Sahni demonstrate the wide variation in shape
360 SAHNI'S TYPES
naturally to be found in gerontic material of any species, while localized type-
specimens all fit into the scatter plot for their locality. It is also concluded that
differences in the cardinalia demonstrated in the often gerontic types cannot be
used to distinguish between species of Carneithyris in the English Campanian.
Neither the growth of the specimens, their outline nor their cardinalia show any
distinct trend which may be used for erecting species on a stratigraphical or geo-
graphical basis. In the available material I can recognize only one species of
Carneithyris in the Upper Campanian of England, namely C. carnea (J. Sowerby).
VII. CONCLUDING REMARKS
On the basis of the present material I am unable to subdivide the Campanian
carneithyridines into species which are visibly distinguishable or statistically valid.
In the specimens from the Upper Campanian the only trend which I have detected
is a tendency to develop smaller mature individuals towards the Campanian-
Maastrichtian boundary. Single specimens, including those called Magnithyris and
Carneithyris circularis by Sahni, seem to have retained to a great age certain juvenile
characters such as thin shells, a circular outline, a beak which is not strongly incurved
and a fairly large foramen. However, these and other external and internal features
do not appear in any particular facies or horizon. On the contrary, they show a
scattered occurrence throughout the Upper Campanian of Norfolk and can be
considered to be due to peculiarities in the genetical composition of the individuals
concerned. I thus consider that all the available carneithyridines from the Upper
Campanian of Norfolk should be referred to the single species Carneithyris carnea.
In the Lower Maastrichtian chalk of Sidestrand and Trimingham, C. carnea is
replaced by C. subcardinalis (Sahni), which is distinguishable from C. carnea on the
basis of its internal features. Unfortunately the critical sediments at the Campanian-
Maastrichtian boundary are not exposed in Norfolk and the replacement of the one
species by the other, which would establish whether it is gradual, sharp or with over-
lap, cannot be studied in detail. C. carnea is still present at Bramerton and C.
subcardinalis is found in the lowest exposed Maastrichtian at Sidestrand.
The subfamily Carneithyridinae thus contains only one genus, Carneithyris, the
stratigraphical range of which is poorly known. Muir-Wood (1965) offered no sug-
gestions as to the phyletic relationships of the subfamily ; its sudden appearance in
the Upper Campanian of north-west Europe is, so far, an enigma. Some terebra-
tulids from the Lower Campanian of the Hampshire Basin (R. M. Brydone collection,
Institute of Geological Sciences, London) resemble carneithyridines externally but
they have not been opened and dissected. Apart from these uncertain specimens,
no carneithyridines are known of pre-Upper Campanian age. Carneithyris is known
from the Maastrichtian and Danian of northern Europe (Asgaard 1963, 1970 ;
Steinich 1965 ; Popiel-Barczyk 1968 ; Surlyk 1972).
Carneithyris probably invaded the chalk facies from a more coastal area, its
ancestors having been 'normal' terebratulids with clearly distinguished cardinalia
with ventrally concave outer hinge-plates (as seen in the specimen called Magnithyris
truncata) and a stout functional pedicle. An experimental phase was passed through
OF CARNEITHYRIDINAE 361
in the Upper Campanian chalk where the animals retained a thin, functional pedicle,
possibly fastened to a small object as substrate used as a drag anchor, as seen in the
Recent terebratellid Laqueus californianus on coarse sandy bottoms. During this
phase a heavy posterior end with swollen and fused cardinalia was developed. In
the Maastrichtian, Carneithyris increased the weight of the callus deposits in the
posterior part of the valves and blocked the foramen, thereby becoming perfectly
adapted for a free-living life habit as a 'self-righting tumbler' in the soft, fine-grained
sea floor (Steinich 1965 ; Surlyk 1972). Stocks in the marginal calcarenite facies
meanwhile retained a functional pedicle and had a less heavily weighted shell.
In Denmark and Sweden, Carneithyris disappeared with the introduction of
calcarenite facies in the lowermost Tertiary and first migrated back into this area in
the Middle Danian. In the calcarenite facies the genus developed a sulcate frontal
commissure which was possibly a further development of the slightly sulcate to
paraplicate commissure seen in some specimens from high Paramoudra Chalk and
Bramerton, Norfolk. The Danian specimens furthermore have cardinalia very
much like those of the Campanian C. carnea and in most cases they possessed a
functional, though very slender pedicle (Asgaard 1963).
VIII. REFERENCES
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Bull. geol. Surv. Gt Br., London, 27 : 271-288, pis 20, 21.
ZAKHARIEVA-KOVACEVA, K. 1947. Les brachiopodes Supracr6taciques de la Bulgarie. Spis.
bulg. geol. Druzh., Sofia, 15-19 : 247-274.
IX. INDEX
An asterisk (*) denotes a figure ; the page numbers of the principal references are printed in
bold type.
Argyrotheca 338 Belemnitella 339
Attoe's Pit, Catton 324, 329, 341 mucronata Zone 323
Birley, C. 330
Bayfield collection 324, 326, 328-31, 333-5 Blake, J. H. 332
Beeston Chalk 323-4, 327, 330, 332, 338, Bramerton 339, 343-4, 346*. 347, 348*,
340-1 353, 355, 358-61, 358*
Belemnella 339 British Museum (Natural History) 321-5,
lanceolata Zone 325 339
occidentalis cimbrica Zone 325 Bromley, Dr R. G. 321
occidentalis Zone 325, 336 Brown, J. 332
INDEX
363
Brydone, R. M., collection 323-5, 339, 360
Bulgaria 322
Caistor St Edmunds 345-7, 346*, 352*,
353-5. 358-9, 358*
Campanian 320-3, 326, 333, 338-9, 341,
343, 36o
Campling's Pit, see Edward's Pit
cancellothyridines 338
cardinalia, cardinal process 321, 323,
341-3, 341*
Caribbean Sea 338
Carneithyridinae, carneithyridines 317-62 ;
322, 338
English collections 320
monovariate analyses 344-5
Carneithyris 320-3, 326, 328, 331, 333-4,
336-9, 360-1
evolution and ontogeny 321-2
stratigraphical range 360
acuminata 321, 328, 329, 335, 342, 358 ;
pl- 5, fig. 3
carnea 320, 322, 326-7, 336, 341*, 342-3,
351, 356, 361 ; pi- 1, figs 1-3 ; pl. 3, fig. 3
circularis 321-2, 326-7, 328, 334-5, 342,
355, 358, 360 ; pl. 3, figs i, 2 ; pl. 4,
figs 6, 7
daviesi 321-2, 328, 331, 334, 337, 341-3,
341*, 358 ; pl. 6, figs 1-4 ; pl. 7, fig. i
elongata 322, 327, 329, 342-3, 351 ; pl. 2,
figs 1-3 ; pl. 4, fig. 5
gracilis 322 ; see Pulchrithyris
norvicensis 321, 326, 328, 329, 341*, 342,
358 ; pl. 5, figs 8, ii ; pl. 6, fig. 5
ornata 322, 331, 333, 342-3, 351 ; pl. 4,
figs 11, 12
subcardinalis 320, 323, 338-9, 360
subovalis 321-2, 326, 330, 341-2, 341*,
358 ; pl. 4, figs 3, 4
subpentagonalis 321-2, 326, 327-8, 329,
341-2, 355, 358; pl. 7, figs 2, 3
uniplicata 321-2, 326, 330, 341-2, 351 ;
pl. 4, fig. 9
variabilis 321-2, 328-9, 341-2, 358 ;
pl. 5, fig. i ; pl. 7, fig. 4
Catton Grove 345-7, 346*, 353, 355, 356*,
358-9, 358*
Pit 332
Sponge Bed 323-4, 327, 340-1
'Catton' 324, 327, 345-7, 346*, 353, 355,
356*, 358-9, 358*
Chalk, white 321, 325, 338
glacially transported 324
Charing, Kent 332-3
Chatwinothyris 321-3, 335-7
ciplyensis 322
curiosa 321-2, 336, 337-8 ; pl. 8, fig. 5
gibbosa 321, 338 ; pl. i, fig. 4
lens 322-3
subcardinalis 321-2, 335-6, 337 ; pl. 8,
figs 1-4
symphytica 321, 336-7, 341*, 342, 358 ;
Pl- 2, fig. 5
Christensen, W. K. 320
Ciply, Craie Phosphate 322
coccoliths 334
Cockburn, C. F. 331, 333
colour pattern 331
Craie Phosphate de Ciply 322
Cretaceous, Upper 321 ; see Campanian,
Maastrichtian, etc.
Crown Point, see Whitlingham
Danian 320, 338, 360-1
Davidson collection 321, 326-8
Denmark 320, 322, 338, 361
Eaton Chalk 323
Edward's Pit 330
Egelund, H. 321
Ellipsothyris 321-2, 335
similis 321, 326, 334-5, 337, 341*, 342-3,
358 ; pl. 4, fig. 10 ; pl. 7, fig. 5
Fitch collection 324-5, 327
Frettenham 344, 346*, 347, 352*, 353-5,
358-9, 358*
Geological Survey of Great Britain, see
Institute of Geological Sciences, London
Gibbithyris 334
Goff, J. 339
Grey Beds (Chalk) 325, 336
Hampshire Basin 360
Harford Bridges 332, 345-7, 346*, 353-5,
357*, 358-9, 358*
hinge-parts 321
historical review 321-3
Institute of Geological Sciences, London
320-1, 323, 325, 333, 339, 360
364
INDEX
King collection 324-5
Laqueus californianus 361
Laur, A. 335-6
Leader, M. 339
Lollard's Pit 324, 332
lunata reef 336
Maastricht, Holland 325
Maastrichtian, Lower 320-3, 325, 336-8, 360
Upper 336, 338
McWilliams, Dr B. 320, 325
Magdalen Chapel 324, 330, 332 ; see
Mousehold
Magnithyris 322, 333, 360
magna 321, 333-4, 335, 342, 351, 358 ;
pi. 4, fig. i ; pi. 5, fig. 10
truncata 322, 333, 334, 342, 358, 360 ;
pi. 4, fig. 2
material 339
stratigraphical distribution 340*
Micr aster coranguinum Zone 334
morphology, external 343-5
Mosasaurus 324
Mousehold 324, 330, 332-3, 345-7, 346*,
353-5. 354*. 355*. 358-9, 358*
mucronata Chalk, basal 323
Muir-Wood, H. M. 324, 327, 332
Mundesley 324
'non-lunata' reef 336
Norfolk 321, 339, 360 ; see also under
localities
Norwich area 320, 322, 325-36, 338 ; see
Norfolk
Upper Chalk of 323-4
Norwich Castle Museum 320-1, 323, 327,
330. 339
old collection of 325, 341
Orinithothyris 322
carinata 321, 329, 335, 342, 358 ; pi. 5,
fig. 2
'Ostrea lunata' 325, 336-8 ; see lunata reef,
'non-lunata' reef
vesicularis Bed 335
Owen, E. F. 320, 324
Paramoudra Chalk 323-4, 327, 330, 333,
339-41. 36i
Peake, N. B. 320, 324
'pearl' 331
Peel, Dr J. S. 321
Perch-Nielsen, Dr K. 334
Piarothyris 322, 334
rotunda 321, 334 ; pi. 3, fig. 4
plesiotype, use of term 326 (footnote)
Poland 322, 336
Porosphaera beds 325
Postwick, Postwick Grove 324
Pulchrithyris 321-2, 332-3
extensa 321, 333, 342, 358 ; pi. 4, fig. j
gracilis 321-2, 326, 332-3, 342 ; pi. 5,
figs 4-7
regression lines 347-59
Reid, C. 335
Rosenkrantz, Professor A. 321
Rowe, A. W. 324
collection 322-3, 326, 330, 332-3, 336,
339
Riigen, I. of, Germany 322, 324, 335-6
Sahni, M. R. 320-62 passim
material of carneithyridines 325-38
phylogenetic tree and stages of 322,
330-1, 339-41
specimens collected by 329
Savin 337
St James's Hollow 324
Santonian 334
'self-righting tumbler' 323, 361
senile specimens 355, 358-9, 358*
Sidestrand 324, 360
Sowerby collection 321, 326-7
'splitting' 338
Sponge Beds 325
statistical analyses 345-59
Surlyk, Dr F. 320, 325
Sweden, Cretaceous of 322, 361
Terebratula carnea 320-1, 324, 326 7
elongata 320-1, 324, 332
incisa 323
lens 323
'lens' 322-3
Terebratulidae 320-2, 360
Thorpe Hamlets 324
Limekiln 324, 332-3, 344, 346*, 347,
349*. 353. 358-9, 358*
Lunatic Asylum Pit 324, 346*
St Andrew 333
Tollgate 324
INDEX 365
'Thorpe' 324, 330-1, 333, 344, 346*, 347, Walker, J. F. 335
351*. 353. 358-9, 358* Westlegate 345-7, 346*. 352*, 353-4,
Trimingham 324-5, 326, 335-8, 360 358-9, 358*
Chalk 325, 360 Weybourne Chalk 323-4, 327, 332-3,
Trowse' 324, 326-7, 332-3, 344, 346*, 347, 339-41, 343
351*, 353, 358-9, 358* Whitlingham (Crown Point Pit) 324, 326,
Tuffeau of Maastricht 325 330, 332-3, 344, 346*, 347, 350*, 353,
type-material, provenance of 323-5 358-9, 358*
Withers, T. H. 324
Wood, C. J. 320, 324-5, 332, 334, 336, 339
Vistula valley, Poland 322 Woodward, S., collection 324-5
Wroxham pipeline 344, 348*
U. ASGAARD
INSTITUT FOR HISTORISK GEOLOGI OG PAUEONTOLOGI
0STERVOLDGADE IO
1350 K0BENHAVN K
DENMARK Accepted for publication i April 1974
32
PLATE i
Carneithyris carnea (J. Sowerby, 1812) ( p. 326, see also PI. 3, fig. 3)
FIG. la-c. Lectotype, B 49836, x 2.
FIG. 2. Paralectotype, B 49837, x 2.
FIG. 3a-c. Davidson's specimen, B 49852, x 2.
Chatwinothyris gibbosa Sahni, i925a (p. 338)
FIG. 4a, b. Holotype, B 45670, ventral and posterior views of the cardinalia, x 4.
Bull. Br. Mus. nat. Hist. (Geol.) 25, 5
PLATE i
PLATE 2
Carneithyris elongata (J. de C. Sowerby, 1823) (p. 327, see also PL 4, fig. 5)
FIG. la-c. Lectotype, B 49823, x 2.
FIG. 2a, b. Paralectotype, B 49824, dorsal and anterior-dorsal views, x 2.
FIG. 3a-c. Davidson's specimen, B 6101, x 2.
Chatwinothyris symphytica Sahni, 1925 (p. 336)
FIG. 4. Holotype, GSM 47523, detail of cardinalia, x 4. Note the pitted callus deposits
and the extremely prominent cardinal process.
Bull. BY. Mus. nat. Hist. (Geol.) 25, 5
PLATE 2
3b
PLATE 3
Carneithyris circularis Sahni, 1925 (p. 328, see also PL 4, figs 6, 7)
FIG. la-c. Paratype, B 49862, x 2.
FIG. 2a, b. Paratype, B 45603, x 2 ; detail of cardinalia, x 4.
Carneithyris carnea (J. Sowerby, 1812) (p. 326, see also PI. i, figs 1-3)
FIG. 3a, b. 'Plesiotype', B 45600, x 2 ; detail of cardinalia, x 4.
Piarothyris rotunda Sahni, 1925 (p. 334)
FIG. 4. Holotype, 18 KCN, detail of cardinalia, x 4.
Bull. Br. Mus. nat. Hist. (Geol.) 25, 5
PLATE 3
3a
PLATE 4
All figures except Fig. 1 1 show details of the cardinalia.
Magnithyris magnet Sahni, 1925 (p. 333, see also PL 5, fig. 10)
FIG. i. Holotype, GSM 48488, x 4.
Magnithyris truncata Sahni, 1929 (p. 334)
FIG. 2. Holotype, B 45606, x 4.
Carneithyris subovalis Sahni, ig25a (p. 330)
FIG. 3. Holotype, B 15159, x 4.
FIG. 4. Paratype, Norwich Castle Museum, no number, x 4.
Carneithyris elongata (J. de C. Sowerby, 1823) (p. 327, see also PI. 2, figs 1-3)
FIG. 5. 'Plesiotype', B 45243, x 4.
Carneithyris circularis Sahni, 1925 (p. 328, see also PL 3, figs i, 2)
FIG. 6. Holotype, 15 KCN, x 4.
FIG. 7. Paratype, B 45604, x 4.
Pulchrithyris extensa Sahni, 1925 (p. 333)
FIG. 8. Holotype, 7 KCN. Ventral view of the remains of the brachial valve, x 4.
Carneithyris uniplicata Sahni, ig25a (p. 330)
FIG. 9. Holotype, GSM 485 1 8, x 4.
Ellipsothyris similis Sahni, 1925 (p. 334, see also PL 7, fig. 5)
FIG. 10. Holotype, 14 KCN, x 4.
Carneithyris ornata Sahni, 1929 (p. 331)
FIG. ii. Holotype, GSM 48498. Dorsal view of brachial valve, x 2.
FIG. 12. Same, ventral view of the posterior part of the brachial valve, showing cardinalia,
very clear muscle impressions, and slightly pitted callus, x 4.
Bull. Br. Mus. nat. Hist. (Geol.) 25, 5
PLATE 4
PLATE 5
All figures show details of the cardinalia.
Carneithyris variabilis Sahni, 1925 (p. 328, see also PL 7, fig. 4)
FIG. i. Holotype, 14 CMN, x 4.
Ornithothyris carinata Sahni, 1925 (p. 335)
FIG. 2. Holotype, 17 KCN, x 4.
Carneithyris acuminata Sahni, 1925 (p. 329)
FIG. 3. Holotype, 19 CMN, x 4.
Pulchrithyris gracilis Sahni, 1925 (p. 332)
FIG. 4. B 98123, X4-
FIG. 5. B 46300, x 4.
FIG. 6. Paratype, GSM 48485, x 4 ; the loop is glued on upside down.
FIG. 7. Holotype, GSM 48487, x 4.
Carneithyris norvicensis Sahni, 1925 (p. 329, see also PL 6, fig. 5)
FIG. 8. Possible paratype, B 52067, x 4.
FIG. ii. Holotype, GSM 44494, x 4.
Carneithyris cf. carnea (J. Sowerby) (p. 326)
FIG. 9. 27 KCN, x 4.
Magnithyris magna Sahni, 1925 (p. 333, see also PL 4, fig. i)
FIG. 10. Presumed paratype, B 15149, x 4.
Bull. Br. Mus. nat. Hist. (Geol.) 25, 5
PLATE 6
All figures except Figs i and 2 show details of the cardinalia.
Carneithyris daviesi Sahni, 19253 (p. 331, see also PL 7, fig. i)
FIG. la, b. Paratype, B 459, x 2.
FIG. 2a, b. Same, details of pedicle valve, oblique views to show the strongly swollen
tooth bases, x 4.
FIG. 3. Holotype, B 45599, x 4.
FIG. 4. The third specimen, B 45642, x 4.
Carneithyris norvicensis Sahni, 1925 (p. 329, see also PL 5, figs 8, n)
FIG. 5. Possible paratype, B 45610, x 4.
Bull. Br. Mus. nat. Hist. (Geol.) 25, 5
PLATE 6
1b
PLATE 7
All figures show details of the cardinalia.
Carneithyris daviesi Sahni, ig25a (p. 331, see also PL 6, figs 1-4)
FIG. la-c. Paratype, B 459, ventro-lateral, ventral and ventro-posterior views, x 4.
Carneithyris subpentagonalis Sahni, 1925 (p. 327)
FIG. 2a, b. Holotype, 8 KCN, ventro-lateral and ventral views, x 4.
FIG. 3. Paratype, GSM 44491, ventral view, x 4.
Carneithyris variabilis Sahni, 1925 (p. 328, see also PI. 5, fig. i)
FIG. 4. Paratype, 13 CMN, ventral view, x 4.
Ellipsothyris similis Sahni, 1925 (p. 334, see also PL 4, fig. 10)
FIG. 5. ? Paratype, B 45653, ventral view, x 4.
Bull. Br. Mus. nat. Hist. (Geol.) 25, 5
PLATE 7
PLATE 8
All figures show details of the cardinalia.
Chatwinothyris subcardinalis Sahni, 1925 (p. 335)
FIG. la-c. Holotype, GSM 44501, ventral, ventro-posterior and posterior views, x 4.
FIG. 2a, b. Paratype, B 46326, ventral and ventro-posterior views, x 4.
FIG. 3a, b. Another specimen, B 46327, ventral and ventro-posterior views, x 4.
FIG. 4a, b. Another specimen, B 21266, ventral and ventro-posterior views, x 4.
Chatwinothyris curiosa Sahni, iQ25a (p. 337)
FIG. 5a, b. Holotype, B 45669, ventral and ventro-posterior views, x 4.
FIG. 5c-e. Same, various oblique views of the cardinalia and brachidium showing the
exotic loop, x 4.
Bull. Br. Mus. nat. Hist. (Geol.) 25, 5
PLATE 8
A LIST OF SUPPLEMENTS
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